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We review low and high field magnetotransport in 80 nm-thick strained HgTe, a material that belongs to the class of strong three-dimensional topological insulators. Utilizing a top gate, the Fermi level can be tuned from the valence band…

Mesoscale and Nanoscale Physics · Physics 2020-07-02 Johannes Ziegler , Dmitriy A. Kozlov , Nikolay N. Mikhailov , Sergey A. Dvoretsky , Dieter Weiss

We propose a minimal effective two-dimensional Hamiltonian for HgTe/CdHgTe quantum wells (QWs) describing the side maxima of the first valence subband. By using the Hamiltonian, we explore the picture of helical edge states in tensile and…

Mesoscale and Nanoscale Physics · Physics 2018-04-11 S. S. Krishtopenko , F. Teppe

Topological states of matter have attracted a lot of attention due to their many intriguing transport properties. In particular, two-dimensional topological insulators (2D TI) possess gapless counter propagating conducting edge channels,…

Mesoscale and Nanoscale Physics · Physics 2019-10-11 G. M. Gusev , Z. D Kvon , E. B. Olshanetsky , N. N. Mikhailov

Time-dependent perturbations can drive a trivial two-dimensional band insulator into a quantum Hall-like phase, with protected nonequilibrium states bound to its edges. We propose an experiment to probe the existence of these topological…

Mesoscale and Nanoscale Physics · Physics 2014-11-18 Benjamin M. Fregoso , Jan P. Dahlhaus , Joel E. Moore

We report on transport and capacitance spectroscopy study of two kinds of quantum wells, namely Cd$_{0.02}$Hg$_{0.98}$Te and Cd$_{0.06}$Hg$_{0.94}$Te with the thicknesses of 7.4 and 11.5 nm, accordingly. The fraction of Cd was chosen in a…

Mesoscale and Nanoscale Physics · Physics 2019-01-30 M. L. Savchenko , D. A. Kozlov , Z. D. Kvon , N. N. Mikhailov , S. A. Dvoretsky , B. A. Piot

The 2D HgTe quantum well is analyzed based on the assumption that the width fluctuations convert the system to a random mixture of domains with positive and negative energy gaps. The borders between ordinary and topological insulator phases…

Mesoscale and Nanoscale Physics · Physics 2019-02-20 M. M. Mahmoodian , M. V. Entin

We study the electronic transport across an electrostatically-gated lateral junction in a HgTe quantum well, a canonical 2D topological insulator, with and without applied magnetic field. We control carrier density inside and outside a…

We report transport studies on a three dimensional, 70 nm thick HgTe layer, which is strained by epitaxial growth on a CdTe substrate. The strain induces a band gap in the otherwise semi-metallic HgTe, which thus becomes a three dimensional…

Mesoscale and Nanoscale Physics · Physics 2015-03-17 C. Brüne , C. X. Liu , E. G. Novik , E. M. Hankiewicz , H. Buhmann , Y. L. Chen , X. L. Qi , Z. X. Shen , S. C. Zhang , L. W. Molenkamp

We calculate bulk transport properties of two-dimensional topological insulators based on HgTe quantum wells in the ballistic regime. Interestingly, we find that the conductance and the shot noise are distinctively different for the…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 E. G. Novik , P. Recher , E. M. Hankiewicz , B. Trauzettel

For 2D topological insulators with strong electron-hole hybridization, such as HgTe/CdTe quantum wells, the widely used 4 x 4 k.p Hamiltonian based on the first electron and heavy hole sub-bands yields an equal number of physical and…

Mesoscale and Nanoscale Physics · Physics 2018-08-01 Philip Klipstein

Topological insulators are a newly discovered phase of matter characterized by a gapped bulk surrounded by novel conducting boundary states. Since their theoretical discovery, these materials have encouraged intense efforts to study their…

We study the evolutions of the nonmagnetic disorder-induced edge states with the disorder strength in the HgTe/CdTe quantum wells. From the supercell band structures and wave-functions, it is clearly shown that the conducting helical edge…

Mesoscale and Nanoscale Physics · Physics 2012-05-04 Liang Chen , Qin Liu , Xulin Lin , Xiaogang Zhang , Xunya Jiang

Recently, level crossings in the energy bands of crystals have been identified as a key signature for topological phase transitions. Using realistic models we show that the parameter space controlling the occurrence of level coincidences in…

Mesoscale and Nanoscale Physics · Physics 2012-11-19 R. Winkler , L. Y. Wang , Y. H. Lin , C. S. Chu

We study theoretically 2D HgTe/CdTe quantum well topological insulator (TI) illuminated by circularly polarized light with frequencies higher than the difference between the equilibrium Fermi level and the bottom of the conduction band (THz…

Mesoscale and Nanoscale Physics · Physics 2015-10-26 Vardan O. Kaladzhyan , Pavel P. Aseev , Sergey N. Artemenko

In this work, we used 20 nm thick CdTe/SnTe/CdTe [001] quantum wells to make 6- and 8-terminal nano-structures with the etched cross-junctions of sub-micron width with walls directed along the [10], [01], and [11] surface crystallographic…

Mesoscale and Nanoscale Physics · Physics 2025-03-11 Dawid Śnieżek , Cezary Śliwa , Krzysztof Dybko , Jarosław Wróbel , Piotr Dziawa , Tomasz Wojtowicz , Tomasz Story , Jerzy Wróbel

The exploration of topological phases remains a cutting-edge research frontier, driven by their promising potential for next-generation electronic and quantum technologies. In this work, we employ first-principles calculations and…

Materials Science · Physics 2026-03-06 Sibin Lü , Jun Hu

The time evolution of a wave packet is a tool to detect topological phase transitions in two-dimensional Dirac materials, such as graphene and silicene. Here we extend the analysis to HgTe/CdTe quantum wells and study the evolution of their…

Mesoscale and Nanoscale Physics · Physics 2025-03-18 A. Mayorgas , M. Calixto , N. A. Cordero , E. Romera , O. Castaños

We study a topological phase transition between a normal insulator and a quantum spin Hall insulator in two-dimensional (2D) systems with time-reversal and two-fold rotation symmetries. Contrary to the case of ordinary time-reversal…

Mesoscale and Nanoscale Physics · Physics 2017-04-13 Junyeong Ahn , Bohm-Jung Yang

We present the first experimental study of the double-quantum-well (DQW) system made of 2D layers with inverted energy band spectrum: HgTe. The magnetotransport reveals a considerably larger overlap of the conduction and valence subbands…

Mesoscale and Nanoscale Physics · Physics 2016-03-14 M. V. Yakunin , A. V. Suslov , M. R. Popov , E. G. Novik , S. A. Dvoretsky , N. N. Mikhailov

Quantum spin Hall (QSH) insulators have unique electronic properties, comprising a band gap in their two-dimensional interior and one-dimensional spin-polarized edge states in which current flows ballistically. In scanning tunneling…