Condensed Matter

2186 KiB

Open AccessOpinion

Reflections on the 66th Lindau Nobel Laureaute Meeting

by Alex J. Kruchkov

Condens. Matter 2016, 1(1), 13; https://doi.org/10.3390/condmat1010013 - 20 Dec 2016

Cited by 1 | Viewed by 4185

Abstract

This June, I was one of a group of young scientists sat in the whispering Theatre of Lindau [...] Full article

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792 KiB

Open AccessArticle

An Analytical Model for Evaluation of the Properties of Metallic Coatings in RF Structures

by Giovanni Castorina, Augusto Marcelli, Francesca Monforte, Stefano Sarti and Bruno Spataro

Condens. Matter 2016, 1(1), 12; https://doi.org/10.3390/condmat1010012 - 17 Dec 2016

Cited by 2 | Viewed by 3047

Abstract

A simple analytic model based on the equations of the propagation matrices theory has been developed in order to evaluate the effective skin depth of coated metallic surfaces. With particular attention to the R&D of highly-performing accelerating structures, different thick coatings with excellent [...] Read more.

A simple analytic model based on the equations of the propagation matrices theory has been developed in order to evaluate the effective skin depth of coated metallic surfaces. With particular attention to the R&D of highly-performing accelerating structures, different thick coatings with excellent mechanical and electrical properties have been considered such as molybdenum and its oxides, p-doped SiC, and TiN. Calculations show that copper coated with a p-type SiC may exhibit an improved hardness and a higher thermal resistance. Combined with experimental tests, this study may support the identification of reliable multilayers capable of improving the higher power performance of radio-frequency (RF) structures in terms of the accelerating gradient in order to increase the resistance to the high thermal stress of structures made with copper. Full article

(This article belongs to the Special Issue Selected Papers from The 13th Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN 2016))

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2919 KiB

Open AccessArticle

Early Stage of Sb Ultra-Thin Film Growth: Crystal Structure and Electron Band Structure

by Mirosław Stróżak, Marek Kopciuszyński, Agnieszka Stępniak-Dybala, Mariusz Krawiec and Mieczysław Jałochowski

Condens. Matter 2016, 1(1), 11; https://doi.org/10.3390/condmat1010011 - 16 Dec 2016

Cited by 4 | Viewed by 3457

Abstract

The evolution of the electron band structure upon the reduction of Sb film on a Si(111)-(6 × 6)Au substrate, relevant to topological insulator properties, is experimentally systematically investigated by the reflection high-energy electron diffraction (RHEED), in situ surface electron transport and angular resolved [...] Read more.

The evolution of the electron band structure upon the reduction of Sb film on a Si(111)-(6 × 6)Au substrate, relevant to topological insulator properties, is experimentally systematically investigated by the reflection high-energy electron diffraction (RHEED), in situ surface electron transport and angular resolved photoemission spectroscopy methods. The experiments reveal that a bilayer (BL) of Sb is crystalline but the subsequent three BLs on top of it form amorphous layers. The five-BL-thick film transforms back to the crystalline form. The bilayer as well as 1.2- and 3.8-BL-thick films show the electron band structure with a relatively large energy gap at the Γ point of the Brillouin zone. The theoretically predicted band structure is observed at 4.8 BL coverage. Full article

(This article belongs to the Special Issue Selected Papers from The 13th Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN 2016))

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256 KiB

Open AccessArticle

Theory of Plasmons for Two-Dimensional Materials in the Random Phase Approximation

by Masakazu Ichikawa

Condens. Matter 2016, 1(1), 9; https://doi.org/10.3390/condmat1010009 - 14 Dec 2016

Cited by 7 | Viewed by 4397

Abstract

A theory is derived for plasmons in two-dimensional (2D) materials by using three-dimensional (3D) plasmon theory, which was reported previously in the random phase approximation under high frequency conditions. When the 3D local electron density is expressed by the 2D local electron density [...] Read more.

A theory is derived for plasmons in two-dimensional (2D) materials by using three-dimensional (3D) plasmon theory, which was reported previously in the random phase approximation under high frequency conditions. When the 3D local electron density is expressed by the 2D local electron density

n_{2 D}

multiplied by the delta function in the thickness direction, a self-consistent integral equation for the scalar potential is derived using only

n_{2 D}

and the 2D Coulomb potential. The integral equation consists of the edge and planar plasmon terms which give their resonant frequencies. These frequencies are analytically calculated for uniform 2D atomic layers and nanodisks with step function-like electron densities at their edges. The light emission intensities from the nanodisks are also calculated. These frequencies are compared with those for the 2D and 3D Weyl fermions, i.e., massless Dirac fermions. Full article

(This article belongs to the Special Issue Selected Papers from The 13th Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN 2016))

1662 KiB

Open AccessArticle

Neutron Study of Multilevel Structures of Diamond Gels

by Vasily Lebedev, Yury Kulvelis, Alexander Kuklin and Alexander Vul

Condens. Matter 2016, 1(1), 10; https://doi.org/10.3390/condmat1010010 - 14 Dec 2016

Cited by 25 | Viewed by 3875

Abstract

The structure of a hydrogel consisting of diamond nanoparticles formed by the explosion method has been studied. Small angle neutron scattering has been used as a method for characterization of the gel. Joint approaches for data analysis in reciprocal and direct space have [...] Read more.

The structure of a hydrogel consisting of diamond nanoparticles formed by the explosion method has been studied. Small angle neutron scattering has been used as a method for characterization of the gel. Joint approaches for data analysis in reciprocal and direct space have been developed to restore a multilevel structure. The pristine hydrogel of positively charged diamond particles (~5 nm in size, concentration ~5 wt %), even by four-fold dilution below its formation critical point, (C* ~ 4 wt %) retains practically the original structure where single particles are joined into small groups integrated into chain fractal-type aggregates creating a network. This indicates a local stability of the gel and means a transformation of continuous gel into a system of micro-domains suspended in water. A perfection of the diamond crystals’ facets was revealed that is of principal importance for the configuration of potentials, inducing the diamonds’ electrostatic attraction due to different electric charges of facets. It is distinguished from the results for the suspensions of diamonds in graphene shells that showed a deviation of scattering from Porod’s law. Full article

(This article belongs to the Special Issue Selected Papers from The 13th Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN 2016))

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1855 KiB

Open AccessArticle

Silicene Nanoribbons on Pb-Reconstructed Si(111) Surface

by Agnieszka Stȩpniak-Dybala, Mieczysław Jałochowski and Mariusz Krawiec

Condens. Matter 2016, 1(1), 8; https://doi.org/10.3390/condmat1010008 - 05 Dec 2016

Cited by 11 | Viewed by 5282

Abstract

We report on the initial stage of growing of silicon nanostructures on Pb-induced

\sqrt{3} \times \sqrt{3}

and

\sqrt{3} \times \sqrt{7}

reconstructed Si(111) surfaces. The deposition of 0.75 monolayer of Si at a temperature of around 200 K results in Si nanoribbons a few-nanometers [...] Read more.

We report on the initial stage of growing of silicon nanostructures on Pb-induced

\sqrt{3} \times \sqrt{3}

and

\sqrt{3} \times \sqrt{7}

reconstructed Si(111) surfaces. The deposition of 0.75 monolayer of Si at a temperature of around 200 K results in Si nanoribbons a few-nanometers in length running in three equivalent high symmetry directions of Si(111) surface, as revealed by low temperature scanning tunneling microscopy measurements. The nanoribbons are predominantly 1.6 nm wide and show local

\sqrt{3} \times \sqrt{3}

reconstruction. These findings are interpreted within the framework of silicene nanoribbons grown on a bare Si(111) surface. Full article

(This article belongs to the Special Issue Selected Papers from The 13th Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN 2016))

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Open AccessArticle

Development of Nano-Carbon Biosensors Using Glycan for Host Range Detection of Influenza Virus

by Toshio Kawahara, Hiroaki Hiramatsu, Yasuo Suzuki, Shin-ichi Nakakita, Yasuhide Ohno, Kenzo Maehashi, Kazuhiko Matsumoto, Kazumasa Okamoto, Teruaki Matsuba and Risa Utsunomiya

Condens. Matter 2016, 1(1), 7; https://doi.org/10.3390/condmat1010007 - 01 Dec 2016

Cited by 6 | Viewed by 3551

Abstract

Nano-carbon materials are promising canidates for applications in high performance devices, including highly sensitive biosensors. We have developed a self-alignment process for nano-carbon field effect transistors (FETs), using a carbon nanowall (CNW)—a nano-carbon materials—to fabricate CNW-FETs. We measured the pH dependence of the [...] Read more.

Nano-carbon materials are promising canidates for applications in high performance devices, including highly sensitive biosensors. We have developed a self-alignment process for nano-carbon field effect transistors (FETs), using a carbon nanowall (CNW)—a nano-carbon materials—to fabricate CNW-FETs. We measured the pH dependence of the device properties. The binding molecules are known to be key components for biosensors. We are concentrating on the development of an influenza virus sensor, because the influenza virus is a major public health problem and a highly sensitive sensor is urgently required. We estimated the size of detected molecules of glycan for influenza viruses using atomic force microscopy. The typical molecule size is around 1 nm, and this may be suitable for electronic detection using a FET structure. Full article

(This article belongs to the Special Issue Selected Papers from The 13th Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN 2016))

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2991 KiB

Open AccessArticle

Inner-Shell Ionization and Fragmentation of Isolated Endohedral Fullerene Ions by XUV Radiation

by Stefan Schippers

Condens. Matter 2016, 1(1), 6; https://doi.org/10.3390/condmat1010006 - 21 Nov 2016

Cited by 1 | Viewed by 3223

Abstract

The photon–ion merged-beams technique for photoabsorption studies of ionized nanoparticles with synchrotron radiation is introduced. As an example, recent results from photoionization and photofragmentation of the endohedral fullerene ions Lu₃

{N @ C}_{80}^{+}

, Lu₃ [...] Read more.

The photon–ion merged-beams technique for photoabsorption studies of ionized nanoparticles with synchrotron radiation is introduced. As an example, recent results from photoionization and photofragmentation of the endohedral fullerene ions Lu₃

{N @ C}_{80}^{+}

, Lu₃

{N @ C}_{80}^{2 +}

, and Lu₃

{N @ C}_{80}^{3 +}

are briefly discussed, highlighting the sensitivity and versatility of the experimental technique. Full article

(This article belongs to the Special Issue Selected Papers from The 13th Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN 2016))

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371 KiB

Open AccessArticle

Calculated Effects of Disorder on the Mo Core Levels in Purple Bronze Li₂Mo₁₂O₃₄

by Thomas Jarlborg

Condens. Matter 2016, 1(1), 5; https://doi.org/10.3390/condmat1010005 - 14 Nov 2016

Viewed by 3341

Abstract

The band structures of ordered and thermally disordered Li

_{2}

Mo

_{12}

O

_{34}

are calculated by use of ab initio density functional theory (DFT)–Linear Muffin-Tin Method (LMTO) with a focus on the behavior of the Mo 3d -core levels. It is shown [...] Read more.

The band structures of ordered and thermally disordered Li

_{2}

Mo

_{12}

O

_{34}

are calculated by use of ab initio density functional theory (DFT)–Linear Muffin-Tin Method (LMTO) with a focus on the behavior of the Mo 3d -core levels. It is shown that thermal disorder and zero-point motion lead to substantial core level broadening, and the broadening at room temperature is predicted to be sufficiently larger than at zero degrees to allow for a detection by X-ray photoelectron spectroscopy (XPS) measurements. However, real purple bronze has 10% Li vacancies, and static disorder will attenuate the T-dependent broadening. It is argued that core level spectroscopies could be a useful tool for the measurement of thermal disorders in many materials, especially for those with minor static disorder. Studies of core levels in magnetic materials will be helpful for an understanding of T-dependent spin moments. Full article

(This article belongs to the Special Issue Selected Papers from The 13th Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN 2016))

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1317 KiB

Open AccessArticle

Theoretical Investigations for Strain Relaxation and Growth Mode of InAs Thin layers on GaAs(111)A

by Tomonori Ito, Toru Akiyama and Kohji Nakamura

Condens. Matter 2016, 1(1), 4; https://doi.org/10.3390/condmat1010004 - 08 Nov 2016

Cited by 10 | Viewed by 4556

Abstract

The growth mode of InAs/GaAs(111)A is systematically investigated using our macroscopic theory with the aid of empirical potential calculations that determine parameter values used in the macroscopic theory. Here, stacking-fault tetrahedron (SFT) found in InAs/GaAs(111)A and misfit dislocation (MD) formations are employed as [...] Read more.

The growth mode of InAs/GaAs(111)A is systematically investigated using our macroscopic theory with the aid of empirical potential calculations that determine parameter values used in the macroscopic theory. Here, stacking-fault tetrahedron (SFT) found in InAs/GaAs(111)A and misfit dislocation (MD) formations are employed as strain relaxation mechanisms. The calculated results reveal that the MD formation occurs at the layer thickness h about 7 monolayers (MLs). Moreover, we found that the SFT forming at h about 4 MLs makes surface atoms move upward to reduce the strain energy to promote the two dimensional (2D) growth. Therefore, the SFT in addition to the MD plays an important role in strain relaxation in InAs thin layers on GaAs(111)A. The macroscopic free energy calculations for the growth mode imply that the InAs growth on the GaAs(111)A proceeds along the lower energy path from the 2D-coherent (h ≤ 4 MLs) to the 2D-MD (h ≥ 7 MLs) via the 2D-SFT (4 MLs ≤ h ≤ 7 MLs). Consequently, the 2D growth on the InAs/GaAs(111)A results from strain relaxation due to the formation of the SFT near the surface and the subsequent MD formation at the interface. Full article

(This article belongs to the Special Issue Selected Papers from The 13th Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN 2016))

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133 KiB

Open AccessEditorial

Condensed Matter: A New Open Access Journal

by Antonio Bianconi and Martyn Rittman

Condens. Matter 2016, 1(1), 3; https://doi.org/10.3390/condmat1010003 - 19 Sep 2016

Viewed by 3163

Abstract

Condensed matter physics is a broad and interesting topic [...] Full article

1868 KiB

Open AccessArticle

Cold Atoms in U(3) Gauge Potentials

by Ipsita Mandal and Atri Bhattacharya

Condens. Matter 2016, 1(1), 2; https://doi.org/10.3390/condmat1010002 - 01 Aug 2016

Cited by 2 | Viewed by 3278

Abstract

We explore the effects of artificial

U (3)

gauge potentials on ultracold atoms. We study background gauge fields with both non-constant and constant Wilson loops around plaquettes, obtaining the energy spectra in each case. The scenario of metal–insulator transition for irrational [...] Read more.

We explore the effects of artificial

U (3)

gauge potentials on ultracold atoms. We study background gauge fields with both non-constant and constant Wilson loops around plaquettes, obtaining the energy spectra in each case. The scenario of metal–insulator transition for irrational fluxes is also examined. Finally, we discuss the effect of such a gauge potential on the superfluid–insulator transition for bosonic ultracold atoms. Full article

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2778 KiB

Open AccessArticle

Computational Study of Quasi-2D Liquid State in Free Standing Platinum, Silver, Gold, and Copper Monolayers

by Li-Ming Yang, Ariel B. Ganz, Matthew Dornfeld and Eric Ganz

Condens. Matter 2016, 1(1), 1; https://doi.org/10.3390/condmat1010001 - 02 Mar 2016

Cited by 27 | Viewed by 6165

Abstract

Recently, freestanding atomically thick Fe metal patches up to 10 atoms wide have been fabricated experimentally in tiny pores in graphene. This concept can be extended conceptually to extended freestanding monolayers. We have therefore performed ab initio molecular dynamics simulations to evaluate the [...] Read more.

Recently, freestanding atomically thick Fe metal patches up to 10 atoms wide have been fabricated experimentally in tiny pores in graphene. This concept can be extended conceptually to extended freestanding monolayers. We have therefore performed ab initio molecular dynamics simulations to evaluate the early melting stages of platinum, silver, gold, and copper freestanding metal monolayers. Our calculations show that all four freestanding monolayers will form quasi-2D liquid layers with significant out-of-plane motion and diffusion in the plane. Remarkably, we observe a 4% reduction in the Pt most likely bond length as the system enters the liquid state at 2400 K (and a lower effective spring constant), compared to the system at 1200 and 1800 K. We attribute this to the reduced average number of bonds per atom in the Pt liquid state. We used the highly accurate and reliable Density Functional Theory (DFT-D) method that includes dispersion corrections. These liquid states are found at temperatures of 2400 K, 1050 K, 1600 K, and 1400 K for platinum, silver, gold, and copper respectively. The pair correlation function drops in the liquid state, while the bond orientation order parameter is reduced to a lesser degree. Movies of the simulations can be viewed online (see Supplementary Material). Full article

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Condens. Matter, Volume 1, Issue 1 (December 2016) – 13 articles

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