Journal Description
Condensed Matter
Condensed Matter
is an international, peer-reviewed, open access journal on the physics of condensed matter published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, ESCI (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 20.3 days after submission; acceptance to publication is undertaken in 3.9 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
1.9 (2023);
5-Year Impact Factor:
1.5 (2023)
Latest Articles
The Multi-Detectors System of the PANDORA Facility: Focus on the Full-Field Pin-Hole CCD System for X-ray Imaging and Spectroscopy
Condens. Matter 2024, 9(2), 28; https://doi.org/10.3390/condmat9020028 - 20 Jun 2024
Abstract
PANDORA (Plasmas for Astrophysics Nuclear Decays Observation and Radiation for Archaeometry) is an INFN project aiming at measuring, for the first time, possible variations in in-plasma -decay lifetimes in isotopes of astrophysical interest as a function of thermodynamical conditions of the in-laboratory
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PANDORA (Plasmas for Astrophysics Nuclear Decays Observation and Radiation for Archaeometry) is an INFN project aiming at measuring, for the first time, possible variations in in-plasma -decay lifetimes in isotopes of astrophysical interest as a function of thermodynamical conditions of the in-laboratory controlled plasma environment. Theoretical predictions indicate that the ionization state can dramatically modify the -decay lifetime (even of several orders of magnitude). The PANDORA experimental approach consists of confining a plasma able to mimic specific stellar-like conditions and measuring the nuclear decay lifetime as a function of plasma parameters. The -decay events will be measured by detecting the -ray emitted by the daughter nuclei, using an array of 12 HPGe detectors placed around the magnetic trap. In this frame, plasma parameters have to be continuously monitored online. For this purpose, an innovative, non-invasive multi-diagnostic system, including high-resolution time- and space-resolved X-ray analysis, was developed, which will work synergically with the -rays detection system. In this contribution, we will describe this multi-diagnostics system with a focus on spatially resolved high-resolution X-ray spectroscopy. The latter is performed by a pin-hole X-ray camera setup operating in the 0.5–20 keV energy domain. The achieved spatial and energy resolutions are 450 µm and 230 eV at 8.1 keV, respectively. An analysis algorithm was specifically developed to obtain SPhC (Single Photon-Counted) images and local plasma emission spectrum in High-Dynamic-Range (HDR) mode. Thus, investigations of image regions where the emissivity can change by even orders of magnitude are now possible. Post-processing analysis is also able to remove readout noise, which is often observable and dominant at very low exposure times (ms). Several measurements have already been used in compact magnetic plasma traps, e.g., the ATOMKI ECRIS in Debrecen and the Flexible Plasma Trap at LNS. The main outcomes will be shortly presented. The collected data allowed for a quantitative and absolute evaluation of local emissivity, the elemental analysis, and the local evaluation of plasma density and temperature. This paper also discusses the new plasma emission models, implemented on PIC-ParticleInCell codes, which were developed to obtain powerful 3D maps of the X-rays emitted by the magnetically confined plasma. These data also support the evaluation procedure of spatially resolved plasma parameters from the experimental spectra as well as, in the near future, the development of appropriate algorithms for the tomographic reconstruction of plasma parameters in the X-ray domain. The described setups also include the most recent upgrade, consisting of the use of fast X-ray shutters with special triggering systems that will be routinely implemented to perform both space- and time-resolved spectroscopy during transient, stable, and turbulent plasma regimes (in the ms timescale).
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(This article belongs to the Special Issue High Precision X-ray Measurements 2023)
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Microstructure and Unusual Ferromagnetism of Epitaxial SnO2 Films Heavily Implanted with Co Ions
by
Rustam I. Khaibullin, Amir I. Gumarov, Iskander R. Vakhitov, Andrey A. Sukhanov, Nikolay M. Lyadov, Airat G. Kiiamov, Dilyara M. Kuzina, Valery V. Bazarov and Almaz L. Zinnatullin
Condens. Matter 2024, 9(2), 27; https://doi.org/10.3390/condmat9020027 - 11 Jun 2024
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In this work, we have studied the microstructure and unusual ferromagnetic behavior in epitaxial tin dioxide (SnO2) films implanted with 40 keV Co+ ions to a high fluence of 1.0 × 1017 ions/cm2 at room or elevated substrate
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In this work, we have studied the microstructure and unusual ferromagnetic behavior in epitaxial tin dioxide (SnO2) films implanted with 40 keV Co+ ions to a high fluence of 1.0 × 1017 ions/cm2 at room or elevated substrate temperatures. The aim was to comprehensively understand the interplay between cobalt implant distribution, crystal defects (such as oxygen vacancies), and magnetic properties of Co-implanted SnO2 films, which have potential applications in spintronics. We have utilized scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM), differential thermomagnetic analysis (DTMA), and ferromagnetic resonance (FMR) to investigate Co-implanted epitaxial SnO2 films. The comprehensive experimental investigation shows that the Co ion implantation with high cobalt concentration induces significant changes in the microstructure of SnO2 films, leading to the appearance of ferromagnetism with the Curie temperature significantly above the room temperature. We also established a strong influence of implantation temperature and subsequent high-temperature annealing in air or under vacuum on the magnetic properties of Co-implanted SnO2 films. In addition, we report a strong chemical effect of ethanol on the FMR spectra. The obtained results are discussed within the model of two magnetic layers, with different concentrations and valence states of the implanted cobalt, and with a high content of oxygen vacancies.
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Open AccessArticle
Enhancing Spectroscopic Experiment Calibration through Differentiable Programming
by
Fabrizio Napolitano
Condens. Matter 2024, 9(2), 26; https://doi.org/10.3390/condmat9020026 - 5 Jun 2024
Abstract
In this work, we present an innovative calibration technique leveraging differentiable programming to enhance energy resolution and reduce the energy scale systematic uncertainty in X-ray spectroscopic experiments. This approach is demonstrated using synthetic data and is applicable in general to various spectroscopic measurements.
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In this work, we present an innovative calibration technique leveraging differentiable programming to enhance energy resolution and reduce the energy scale systematic uncertainty in X-ray spectroscopic experiments. This approach is demonstrated using synthetic data and is applicable in general to various spectroscopic measurements. This method extends the scope of differentiable programming for calibration, employing Kernel Density Estimation (KDE) to achieve a target Probability Density Function (PDF) for a fully differentiable model of the calibration. To assess the effectiveness of the calibration, we conduct a toy simulation replicating the entire detector response chain and compare it with a standard calibration. This ensures a robust and reliable calibration methodology, holding promise for improving energy resolution and providing a more versatile and efficient approach without the need for extensive fine-tuning.
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(This article belongs to the Special Issue High Precision X-ray Measurements 2023)
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Open AccessArticle
The Effective Potential of Scalar Pseudo-Quantum Electrodynamics in (2 + 1)D
by
Leandro O. Nascimento, Carlos A. P. C. Junior and José R. Santos
Condens. Matter 2024, 9(2), 25; https://doi.org/10.3390/condmat9020025 - 30 May 2024
Abstract
The description of the electron–electron interactions in two-dimensional materials has a dimensional mismatch, where electrons live in (2 + 1)D while photons propagate in (3 + 1)D. In order to define an action in (2 + 1)D, one may perform a dimensional reduction
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The description of the electron–electron interactions in two-dimensional materials has a dimensional mismatch, where electrons live in (2 + 1)D while photons propagate in (3 + 1)D. In order to define an action in (2 + 1)D, one may perform a dimensional reduction of quantum electrodynamics in (3 + 1)D (QED4) into pseudo-quantum electrodynamics (PQED). The main difference between this model and QED4 is the presence of a pseudo-differential operator in the Maxwell term. However, besides the Coulomb repulsion, electrons in a material are subjected to several microscopic interactions, which are inherent in a many-body system. These are expected to reduce the range of the Coulomb potential, leading to a short-range interaction. Here, we consider the coupling to a scalar field in PQED for explaining such a mechanism, which resembles the spontaneous symmetry breaking (SSB) in Abelian gauge theories. In order to do so, we consider two cases: (i) by coupling the quantum electrodynamics to a Higgs field in (3 + 1)D and, thereafter, performing the dimensional reduction; and (ii) by coupling a Higgs field to the gauge field in PQED and, subsequently, calculating its effective potential. In case (i), we obtain a model describing electrons interacting through the Yukawa potential and, in case (ii), we show that SSB does not occur at one-loop approximation. The relevance of the model for describing electronic interactions in two-dimensional materials is also addressed.
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(This article belongs to the Special Issue PQED: 30 Years of Reduced Quantum Electrodynamics)
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Open AccessEditorial
Meeting and Working with K. Alex Müller: Personal Memories
by
Annette Bussmann-Holder and Hugo Keller
Condens. Matter 2024, 9(2), 24; https://doi.org/10.3390/condmat9020024 - 8 May 2024
Abstract
On 9 January 2023, K [...]
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(This article belongs to the Special Issue Complexity in Quantum Materials: In Honor of Prof. K.A. Muller)
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Open AccessEditorial
Alex’s Vision in Functional Quantum Matter
by
Davor Pavuna
Condens. Matter 2024, 9(2), 23; https://doi.org/10.3390/condmat9020023 - 18 Apr 2024
Abstract
My ‘In Memoriam’ contribution is very personal, as it includes many human and professional insights that I received from Alex Müller himself [...]
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(This article belongs to the Special Issue Complexity in Quantum Materials: In Honor of Prof. K.A. Muller)
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Open AccessFeature PaperArticle
Optimization of a BEGe Detector Setup for Testing Quantum Foundations in the Underground LNGS Laboratory
by
Kristian Piscicchia, Alberto Clozza, Diana Laura Sirghi, Massimiliano Bazzi, Nicola Bortolotti, Mario Bragadireanu, Michael Cargnelli, Luca De Paolis, Raffaele Del Grande, Carlo Guaraldo, Mihail Iliescu, Matthias Laubenstein, Simone Manti, Johann Marton, Marco Miliucci, Fabrizio Napolitano, Alessio Porcelli, Alessandro Scordo, Francesco Sgaramella, Florin Sirghi, Sandro Tomassini, Oton Vazquez Doce, Johann Zmeskal and Catalina Curceanuadd
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Condens. Matter 2024, 9(2), 22; https://doi.org/10.3390/condmat9020022 - 11 Apr 2024
Abstract
In this work, we report on tests performed with an experimental apparatus prototype based on a broad-energy germanium detector aimed at investigating topical, foundational issues in quantum mechanics: i.e., possible violations of the spin-statistics connection and models of dynamical wave function collapse. Our
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In this work, we report on tests performed with an experimental apparatus prototype based on a broad-energy germanium detector aimed at investigating topical, foundational issues in quantum mechanics: i.e., possible violations of the spin-statistics connection and models of dynamical wave function collapse. Our recent phenomenological analyses demonstrated the importance of pushing the research of new physics signal, predicted in these fields, to an energy range below 10 keV. We describe the development of the dedicated data acquisition system and of the pulse shape discrimination algorithm, which have already allowed us to get a factor two improvement in the lower energy threshold. Future plans are discussed to further improve the lower energy threshold to the level of a few keV.
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(This article belongs to the Special Issue High Precision X-ray Measurements 2023)
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Open AccessReview
Superconductors without Symmetry Breaking
by
Maria Cristina Diamantini
Condens. Matter 2024, 9(2), 21; https://doi.org/10.3390/condmat9020021 - 2 Apr 2024
Abstract
We review the main features of type-III superconductivity. This is a new type of superconductivity that exists in both 2 and 3 spatial dimensions. The main characteristics are emergent granularity and the superconducting gap being opened by a topological mechanism, with no Higgs
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We review the main features of type-III superconductivity. This is a new type of superconductivity that exists in both 2 and 3 spatial dimensions. The main characteristics are emergent granularity and the superconducting gap being opened by a topological mechanism, with no Higgs field involved. Superconductivity is destroyed by the proliferation of vortices and not by the breaking of Cooper pairs, which survive above the critical temperature. The hallmark of this superconductivity mechanism, in 3 spatial dimensions (3D), is the Vogel–Fulcher–Taman scaling of the resistance with temperature.
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(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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Open AccessArticle
Topological Phase Diagram of an Interacting Kitaev Chain: Mean Field versus DMRG Study
by
Giovanni Nunziante, Alfonso Maiellaro, Claudio Guarcello and Roberta Citro
Condens. Matter 2024, 9(1), 20; https://doi.org/10.3390/condmat9010020 - 20 Mar 2024
Abstract
In this work, we study the topological phase transitions of a Kitaev chain generalized by the addition of nearest-neighbor Coulomb interaction. We show the presence of a robust topological phase as a function of the interaction strength and of the on-site energy with
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In this work, we study the topological phase transitions of a Kitaev chain generalized by the addition of nearest-neighbor Coulomb interaction. We show the presence of a robust topological phase as a function of the interaction strength and of the on-site energy with associated non-zero energy Majorana states localized at the chain edges. We provide an effective mean-field model that allows for the self-consistent computation of the mean value of the local particle number operator, and we also perform Density Matrix Renormalization Group numerical simulations based on a tensor network approach. We find that the two methods show a good agreement in reporting the phase transition between trivial and topological superconductivity. Temperature robustness within a physically relevant threshold has also been demonstrated. These findings shed light on an entire class of topological interacting one-dimensional systems in which the effects of residual Coulomb interactions play a relevant role.
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(This article belongs to the Special Issue Multicomponent Superconductivity and Superfluidity)
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Open AccessFeature PaperArticle
Enhancing Performances of the VOXES Bragg Spectrometer for XES Investigations
by
Simone Manti, Fabrizio Napolitano, Alberto Clozza, Catalina Curceanu, Gabriel Moskal, Kristian Piscicchia, Diana Sirghi and Alessandro Scordo
Condens. Matter 2024, 9(1), 19; https://doi.org/10.3390/condmat9010019 - 7 Mar 2024
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Utilizing a dispersive crystal for X-ray Emission Spectroscopy (XES) significantly enhances the energy resolution when compared with spectroscopy performed with just silicon drift detectors. This high resolution is particularly valuable for studying metals, as it offers essential insights into their electronic structures and
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Utilizing a dispersive crystal for X-ray Emission Spectroscopy (XES) significantly enhances the energy resolution when compared with spectroscopy performed with just silicon drift detectors. This high resolution is particularly valuable for studying metals, as it offers essential insights into their electronic structures and chemical environments. Conducting such experiments in the laboratory, as opposed to synchrotron light sources, presents challenges due to the reduced intensities of X-ray tubes and, consequently, low signal rates, with the effect of increasing the acquisition time. In this study, we demonstrate that XES spectra can be acquired within a few hours for a CuNiZn metallic sample alloy while still maintaining a good energy resolution and a large dynamic range. This is achieved with the VOXES spectrometer, developed at INFN National Laboratories of Frascati (LNF), along with a background reduction procedure that enhances the signal from emission lines under study. This study is a showcase for improving the efficiency of XES in tabletop setup experiments.
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Open AccessArticle
Experimental Study on Coefficient of Restitution of Small-Sized Spherical Particles during Low-Speed Impact
by
Tuo Li, Ran Li, Zhipeng Chi, Yuting Zhang and Hui Yang
Condens. Matter 2024, 9(1), 18; https://doi.org/10.3390/condmat9010018 - 5 Mar 2024
Abstract
This study presents experimental investigations on the normal restitution coefficients of a titanium bead (Ti), zirconia bead (ZrO2), and amorphous zirconium alloy sphere (Amor). The research explores the influence of particle diameter and collision velocity on the normal restitution coefficient between
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This study presents experimental investigations on the normal restitution coefficients of a titanium bead (Ti), zirconia bead (ZrO2), and amorphous zirconium alloy sphere (Amor). The research explores the influence of particle diameter and collision velocity on the normal restitution coefficient between two independent, identical spherical particles of different materials. The experimental findings demonstrate that increasing the particle diameter results in more effective plastic deformation, leading to higher energy losses and, subsequently, smaller coefficients of restitution. Similarly, higher particle velocities cause more energy dissipation during collisions, resulting in smaller restitution coefficients. Comparing particles of different materials, those with larger yield strengths exhibit more elastic behavior, experience less initial energy loss due to deformation, and reach the maximum restitution coefficient (elastic state) with fewer collisions. This finding suggests that material properties significantly influence the overall energy dissipation and elastic response in the particles. To validate the experimental results, existing models are compared and discussed. Furthermore, potential physical mechanisms responsible for the observed behavior are explored, providing valuable insights into the collision dynamics in spherical particle interactions. Overall, this study contributes to a better understanding of the factors affecting the normal restitution coefficient in particle collisions, enabling the design and optimization of particle systems for diverse applications in condensed matter and related fields.
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(This article belongs to the Special Issue Progress in Granular Materials Research in the Asia-Pacific Region)
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Open AccessArticle
Design and Optimization of Potentially Low-Cost and Efficient MXene/InP Schottky Barrier Solar Cells via Numerical Modeling
by
Mohammad Saleh N Alnassar
Condens. Matter 2024, 9(1), 17; https://doi.org/10.3390/condmat9010017 - 3 Mar 2024
Cited by 1
Abstract
This paper uses numerical modeling to describe the design and comprehensive analysis of cost-effective MXene/n-InP Schottky barrier solar cells. The proposed design utilizes Ti3C2Tx thin film, a 2D solution-processible MXene material, as a Schottky transparent conductive electrode (TCE).
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This paper uses numerical modeling to describe the design and comprehensive analysis of cost-effective MXene/n-InP Schottky barrier solar cells. The proposed design utilizes Ti3C2Tx thin film, a 2D solution-processible MXene material, as a Schottky transparent conductive electrode (TCE). The simulation results suggest that these devices can achieve power conversion efficiencies (PCEs) exceeding 20% in metal–semiconductor (MS) and metal–interlayer–semiconductor (MIS) structures. Combining the proposed structures with low-cost InP growth methods can reduce the gap between InP and other terrestrial market technologies. This is useful for specific applications that require lightweight and radiation-hard solar photovoltaics.
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(This article belongs to the Topic Applications of Photonics, Laser, Plasma and Radiation Physics)
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Open AccessArticle
Characterization of the SIDDHARTA-2 Setup via the Kaonic Helium Measurement
by
Francesco Sgaramella, Francesco Clozza, Leonardo Abbene, Francesco Artibani, Massimiliano Bazzi, Giacomo Borghi, Mario Bragadireanu, Antonino Buttacavoli, Michael Cargnelli, Marco Carminati, Alberto Clozza, Griseld Deda, Raffaele Del Grande, Luca De Paolis, Kamil Dulski, Carlo Fiorini, Carlo Guaraldo, Mihail Iliescu, Masahiko Iwasaki, Aleksander Khreptak, Simone Manti, Johann Marton, Marco Miliucci, Paweł Moskal, Fabrizio Napolitano, Szymon Niedźwiecki, Hiroaki Ohnishi, Kristian Piscicchia, Fabio Principato, Alessandro Scordo, Michal Silarski, Diana Sirghi, Florin Sirghi, Magdalena Skurzok, Antonio Spallone, Kairo Toho, Marlene Tüchler, Johann Zmeskal and Catalina Curceanuadd
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Condens. Matter 2024, 9(1), 16; https://doi.org/10.3390/condmat9010016 - 28 Feb 2024
Abstract
The aim of the SIDDHARTA-2 experiment is to perform the first measurement ever of the width and shift induced by the strong interaction to the energy transition of kaonic deuterium. This ambitious goal implies a challenging task due
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The aim of the SIDDHARTA-2 experiment is to perform the first measurement ever of the width and shift induced by the strong interaction to the energy transition of kaonic deuterium. This ambitious goal implies a challenging task due to the very low X-ray yield of kaonic deuterium, which is why an accurate and thorough characterization of the experimental apparatus is mandatory before starting the data-taking campaign. Helium-4 is an excellent candidate for this characterization since it exhibits a high yield in particular for the transition, roughly 100 times greater than that of the kaonic deuterium. The ultimate goal of the work reported in this paper is to study the performances of the full experimental setup in view of the kaonic deuterium measurement. This is carried out by measuring the values of the shift and the width for the energy transition of kaonic helium-4, induced by the strong interaction. The values obtained for these quantities, for a total integrated luminosity of ∼31/ , are and . The results, compared to the value of the shift measured by the SIDDHARTA experiment , show a net enhancement of the resolution of the apparatus, providing strong evidence of the potential to perform the challenging measurement of the kaonic deuterium.
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(This article belongs to the Special Issue High Precision X-ray Measurements 2023)
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Open AccessArticle
Universal Short-Time Conductance Behavior Emerges between Two Adjacent Reservoirs
by
Er’el Granot
Condens. Matter 2024, 9(1), 15; https://doi.org/10.3390/condmat9010015 - 26 Feb 2024
Abstract
When a shutter, which differentiates between two adjacent particles’ reservoirs with a voltage gap, is lifted, a current emerges. In this paper, the temporal dynamics of this emerging current is analyzed. The main results are as follows: (A) the current’s prefactor in the
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When a shutter, which differentiates between two adjacent particles’ reservoirs with a voltage gap, is lifted, a current emerges. In this paper, the temporal dynamics of this emerging current is analyzed. The main results are as follows: (A) the current’s prefactor in the short-time behavior is related to the long-time frequencies, by which the current converges to its equilibrium value (the conductance quantum unit 2e2/h). (B) In the short-time regime, the current is proportional to the square root of the time. (C) The maximum overshoot conductance is bounded by Gmax = ζe2/h, where ζ is a universal value which is very close to Euler’s number. (D) Most of these results are valid for a thin wire in 3D, even in the presence of electron–electron interactions.
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(This article belongs to the Special Issue New Advances in Condensed Matter Physics)
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Open AccessFeature PaperArticle
The Shrinking Fermi Liquid Scenario for Strange-Metal Behavior from Overdamped Optical Phonons
by
Giovanni Mirarchi, Marco Grilli, Götz Seibold and Sergio Caprara
Condens. Matter 2024, 9(1), 14; https://doi.org/10.3390/condmat9010014 - 6 Feb 2024
Abstract
We discuss how the interaction of electrons with an overdamped optical phonon can give rise to a strange-metal behavior over extended temperature and frequency ranges. Although the mode has a finite frequency, an increasing damping shifts spectral weight to progressively lower energies so
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We discuss how the interaction of electrons with an overdamped optical phonon can give rise to a strange-metal behavior over extended temperature and frequency ranges. Although the mode has a finite frequency, an increasing damping shifts spectral weight to progressively lower energies so that despite the ultimate Fermi liquid character of the system at the lowest temperatures and frequencies, the transport and optical properties of the electron system mimic a marginal Fermi liquid behavior. Within this shrinking Fermi liquid scenario, we extensively investigate the electron self-energy in all frequency and temperature ranges, emphasizing similarities and differences with respect to the marginal Fermi liquid scenario.
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(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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Open AccessArticle
A Theoretical Study of Doping Evolution of Phonons in High-Temperature Cuprate Superconductors
by
Saheli Sarkar
Condens. Matter 2024, 9(1), 13; https://doi.org/10.3390/condmat9010013 - 6 Feb 2024
Cited by 1
Abstract
Hole-doped high-temperature copper oxide-based superconductors (cuprates) exhibit complex phase diagrams where electronic orders like a charge density wave (CDW) and superconductivity (SC) appear at low temperatures. The origins of these electronic orders are still open questions due to their complex interplay and correlated
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Hole-doped high-temperature copper oxide-based superconductors (cuprates) exhibit complex phase diagrams where electronic orders like a charge density wave (CDW) and superconductivity (SC) appear at low temperatures. The origins of these electronic orders are still open questions due to their complex interplay and correlated nature. These electronic orders can modify the phonons in the system, which has also been experimentally found in several cuprates as a softening in the phonon frequency at the CDW vector. Recent experiments have revealed that the softening in phonons in cuprates due to CDW shows intriguing behavior with increasing hole doping. Hole doping can also change the underlying Fermi surface. Therefore, it is an interesting question whether the doping-induced change in the Fermi surface can affect the softening of phonons, which in turn can reveal the nature of the electronic orders present in the system. In this work, we investigate this question by studying the softening of phonons in the presence of CDW and SC within a perturbative approach developed in an earlier work. We compare the results obtained within the working model to some experiments.
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(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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Open AccessFeature PaperArticle
Dynamic Correlations in Disordered Systems: Implications for High-Temperature Superconductivity
by
Takeshi Egami
Condens. Matter 2024, 9(1), 12; https://doi.org/10.3390/condmat9010012 - 3 Feb 2024
Abstract
Liquids and gases are distinct in their extent of dynamic atomic correlations; in gases, atoms are almost uncorrelated, whereas they are strongly correlated in liquids. This distinction applies also to electronic systems. Fermi liquids are actually gas-like, whereas strongly correlated electrons are liquid-like.
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Liquids and gases are distinct in their extent of dynamic atomic correlations; in gases, atoms are almost uncorrelated, whereas they are strongly correlated in liquids. This distinction applies also to electronic systems. Fermi liquids are actually gas-like, whereas strongly correlated electrons are liquid-like. Doped Mott insulators share characteristics with supercooled liquids. Such distinctions have important implications for superconductivity. We discuss the nature of dynamic atomic correlations in liquids and a possible effect of strong electron correlations and Bose–Einstein condensation on the high-temperature superconductivity of the cuprates.
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(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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X-ray Technologies for Astrophysics Missions Supported by the Italian Space Agency
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Marco Miliucci, Angela Volpe, Sergio Fabiani, Marco Feroci, Luca Latronico, Claudio Macculi, Luigi Piro, Matteo D’Andrea, Flavio Gatti, Simonetta Puccetti, Paolo Soffitta and Elisabetta Cavazzuti
Condens. Matter 2024, 9(1), 11; https://doi.org/10.3390/condmat9010011 - 19 Jan 2024
Abstract
The Italian Space Agency plays a key role in the fulfillment of space missions, contributing to the scientific, technological and economic progress in Italy. The agency accomplishes space experiments by collaborating with scientific and industrial entities, supporting them in the realization of new
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The Italian Space Agency plays a key role in the fulfillment of space missions, contributing to the scientific, technological and economic progress in Italy. The agency accomplishes space experiments by collaborating with scientific and industrial entities, supporting them in the realization of new projects able to achieve, over the last two decades, unprecedented results and obtention of fundamental information on the birth and evolution of the universe. The paper describes a selection of X-ray technologies developed by the synergy between the Italian Space Agency and its principal collaborators which contributed to the main scientific results achieved over the years, together with the latest advances addressed to the next astrophysics missions.
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(This article belongs to the Special Issue High Precision X-ray Measurements 2023)
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Open AccessArticle
Search for Novel Phases in Y-Ba-Cu-O Family
by
Danijel Djurek
Condens. Matter 2024, 9(1), 10; https://doi.org/10.3390/condmat9010010 - 17 Jan 2024
Cited by 1
Abstract
In order to search for possible residual minor phases in the Y-Ba-Cu-O family, powdered mixtures of Y2O3 + BaCO3 + CuO and, independently, superconducting compound YBa2Cu3O7−x have been treated in evacuated cells and elevated
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In order to search for possible residual minor phases in the Y-Ba-Cu-O family, powdered mixtures of Y2O3 + BaCO3 + CuO and, independently, superconducting compound YBa2Cu3O7−x have been treated in evacuated cells and elevated temperatures. YBa2Cu3O7−x was reduced to YBa2Cu3O5 by use of the special home-designed Taconis–Knudsen vacuum device. Subsequent doping by oxygen converts produced insulator YBa2Cu3O5 to semiconductor or metal YBa2Cu3O5+x (0 < x < 0.3). In addition to YBa2Cu3O5, 0.05 volume percent of the minor delafossite phase Y2Cu2O4 was spotted in the powder mixture 1/2 Y2O3 + 2BaCO3 + 6Cu2O, heated up to 818 °C in an inert gas atmosphere. An attempt to prepare the insulating bulk delafossite samples was successful, and subsequent doping by oxygen produced novel metallic phases.
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(This article belongs to the Special Issue New Advances in Condensed Matter Physics)
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Open AccessFeature PaperArticle
FL* Approach to the Coexistence of Fermi Arcs with Metal–Insulator Crossover in Strongly Underdoped Cuprates
by
Pieralberto Marchetti
Condens. Matter 2024, 9(1), 9; https://doi.org/10.3390/condmat9010009 - 15 Jan 2024
Abstract
We propose that one can explain the coexistence in the same range of doping and temperature of gapless Fermi arcs with the metal–insulator crossover of in-plane resistivity in strongly underdoped cuprates in terms of the FL* fractionalized Fermi liquid nature of these systems,
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We propose that one can explain the coexistence in the same range of doping and temperature of gapless Fermi arcs with the metal–insulator crossover of in-plane resistivity in strongly underdoped cuprates in terms of the FL* fractionalized Fermi liquid nature of these systems, and that such coexistence is not due simply to disorder effects in the resistivity. The particle excitations of this FL* system derived from variants of the t-J model are the gapless holon carrying charge with small Fermi momentum proportional to the doping, the gapful spinon carrying spin 1/2, and an emergent gauge field coupling them and the hole as a spinon–holon bound state, or more precisely resonance, due to gauge binding, with a Fermi surface respecting the topological Luttinger theorem. In our proposal, Fermi arcs are determined by the hole resonance, whereas the metal–insulator crossover is dominated by spinon–spinon (with subleading holon–holon) gauge interactions, and this dichotomy is able to explain their coexistence.
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(This article belongs to the Special Issue Selected Papers from the 8th International Conference on Superconductivity and Magnetism (ICSM2023))
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