MDPI - Publisher of Open Access Journals

11 pages, 4680 KB

Open AccessArticle

Edge States and Strain-Driven Topological Phase Transitions in Quantum Dots in Topological Insulators

by Benjamin Puzantian, Yasser Saleem, Marek Korkusinski and Pawel Hawrylak

Nanomaterials 2022, 12(23), 4283; https://doi.org/10.3390/nano12234283 - 1 Dec 2022

Cited by 4 | Viewed by 2767

We present here a theory of the electronic properties of quasi two-dimensional quantum dots made of topological insulators. The topological insulator is described by either eight band

\vec{k} \cdot \vec{p}

Hamiltonian or by a four-band

\vec{k} \cdot \vec{p}

Bernevig–Hughes–Zhang [...] Read more.

We present here a theory of the electronic properties of quasi two-dimensional quantum dots made of topological insulators. The topological insulator is described by either eight band

\vec{k} \cdot \vec{p}

Hamiltonian or by a four-band

\vec{k} \cdot \vec{p}

Bernevig–Hughes–Zhang (BHZ) Hamiltonian. The trivial versus topological properties of the BHZ Hamiltonian are characterized by the different topologies that arise when mapping the in-plane wavevectors through the BHZ Hamiltonian onto a Bloch sphere. In the topologically nontrivial case, edge states are formed in the disc and square geometries of the quantum dot. We account for the effects of compressive strain in topological insulator quantum dots by means of the Bir–Pikus Hamiltonian. Tuning strain allows topological phase transitions between topological and trivial phases, which results in the vanishing of edge states from the energy gap. This may enable the design of a quantum strain sensor based on strain-driven transitions in HgTe topological insulator square quantum dots. Full article

(This article belongs to the Special Issue Topological Materials in Low Dimensions)

► Show Figures

Figure 1

10 pages, 952 KB

Open AccessArticle

Topological Properties of the 2D 2-Band System with Generalized W-Shaped Band Inversion

by Zoran Rukelj and Danko Radić

Quantum Rep. 2022, 4(4), 476-485; https://doi.org/10.3390/quantum4040034 - 2 Nov 2022

Cited by 4 | Viewed by 2492

Abstract

We report the topological properties, in terms of the Berry phase, of the 2D noninteracting system with electron–hole band inversion, described by the two-band generalized analogue of the low-energy Bernevig–Hughes–Zhang Hamiltonian, yielding the W-shaped energy bands in the form of two intersecting cones with the gap along the closed continuous loop. We identify the range of parameters where the Berry phase attains qualitatively different values: (a) the integer multiplier of

2 π

, (b) the integer multiplier of

π

, and (c) the nontrivial value between the latter two, which depends on the system parameters. The system thus exhibits the anomalous quantum Hall effect associated with the nontrivial geometric phase, which is presumably tunable through the choice of parameters at hand. Full article

► Show Figures

Figure 1

Search Results (2)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (2)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI