Emergent quantum Hall effects below 50 mT in a two-dimensional topological insulator

  title={Emergent quantum Hall effects below 50 mT in a two-dimensional topological insulator},
  author={Saquib Shamim and Wouter Beugeling and Jan B{\"o}ttcher and Pragya Shekhar and Andreas Budewitz and Philipp Leubner and Lukas Lunczer and Ewelina M. Hankiewicz and Hartmut Buhmann and Laurens W. Molenkamp},
  journal={Science Advances},
Quantum Hall effects emerge at very low magnetic fields from helical edge channels in topological HgTe quantum wells. The realization of the quantum spin Hall effect in HgTe quantum wells has led to the development of topological materials, which, in combination with magnetism and superconductivity, are predicted to host chiral Majorana fermions. However, the large magnetization in conventional quantum anomalous Hall systems makes it challenging to induce superconductivity. Here, we report two… 

Effects of Charge Dopants in Quantum Spin Hall Materials.

  • T. Dietl
  • Physics
    Physical review letters
  • 2023
Semiconductors' sensitivity to electrostatic gating and doping accounts for their widespread use in information communication and new energy technologies. It is demonstrated quantitatively and with

Topological band inversion in HgTe(001): Surface and bulk signatures from photoemission

HgTe is a versatile topological material and has enabled the realization of a variety of topological states, including two- and three-dimensional (3D) topological insulators and topological

Quantitative theory of backscattering in topological HgTe and (Hg,Mn)Te quantum wells: Acceptor states, Kondo effect, precessional dephasing, and bound magnetic polaron

We present the theory and numerical evaluations of the backscattering rate determined by acceptor holes or Mn spins in HgTe and (Hg,Mn)Te quantum wells in the quantum spin Hall regime. The role of

Engineering axion insulator phase in superlattices with inversion symmetry breaking

We study theoretically the interplay between magnetism and topology in three-dimensional HgTe/MnTe superlattices stacked along the (001) axis. Our results show the evolution of the magnetic

Low-Temperature Atomic Layer Deposition of Hafnium Oxide for Gating Applications.

We present a novel low-temperature (30 °C) atomic layer deposition process for hafnium oxide and apply the layers as gate dielectric to fabricate devices out of the thermally sensitive topological

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Hybrid samples combining superconductors with magnetic topological insulators are a promising platform for exploring exotic new transport physics. We examine a Josephson junction of such a system

Counterpropagating topological and quantum Hall edge channels

The survival of the quantum spin Hall edge channels in presence of an external magnetic field has been a subject of experimental and theoretical research. The inversion of Landau levels that

Topological states in superlattices of HgTe class of materials for engineering three-dimensional flat bands

In search of materials with three-dimensional flat band dispersions, using ab-initio computations we investigate how topological phases evolve as a function of hydrostatic pressure and uniaxial strain

Engineering topological phases in triple HgTe/CdTe quantum wells

Quantum wells formed by layers of HgTe between Hg1-x\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy}



A topological Dirac insulator in a quantum spin Hall phase

The direct observation of massive Dirac particles in the bulk of Bi0.9Sb0.1 is reported, which suggests that the observed surface state on the boundary of the bulk insulator is a realization of the ‘topological metal’, which has potential application in developing next-generation quantum computing devices that may incorporate ‘light-like’ bulk carriers and spin-textured surface currents.

Quantum Spin Hall Insulator State in HgTe Quantum Wells

The quantum phase transition at the critical thickness, d = 6.3 nanometers, was independently determined from the magnetic field–induced insulator-to-metal transition, providing experimental evidence of the quantum spin Hall effect.

Effect of magnetic field on electron transport in HgTe/CdTe quantum wells: numerical analysis

The effect of magnetic field on electron transport in the inverted band structure of HgTe/CdTe quantum well is investigated. Although magnetic field breaks the time-reversal symmetry, the quantum

Ballistic quantum spin Hall state and enhanced edge backscattering in strong magnetic fields.

It is shown that the QSH state persists in strong quantizing fields and is identified by counterpropagating (helical) edge channels with nonlinear dispersion inside the band gap, which suggests a rather simple and practical way to probe the quality of quasiballistic QSH devices using magnetoresistance measurements.

Survival of the Quantum Anomalous Hall Effect in Orbital Magnetic Fields as a Consequence of the Parity Anomaly.

It is demonstrated that the QAH phase survives in orbital fields, violates the Onsager relation, and can be therefore distinguished from a quantum Hall (QH) phase.

Quantum anomalous hall effect in Hg1-yMnyTe quantum wells.

This work predicts that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{1-y}Mn{y}Te quantum wells, without an external magnetic field and the associated Landau levels.

Experimental Observation of the Quantum Anomalous Hall Effect in a Magnetic Topological Insulator

The observation of the quantum anomalous Hall (QAH) effect in thin films of chromium-doped (Bi,Sb)2Te3, a magnetic topological insulator shows a plateau in the Hall resistance as a function of the gating voltage without any applied magnetic fields, signifying the achievement of the QAH state.

Interacting topological edge channels

Electrical currents in a quantum spin Hall insulator are confined to the boundary of the system. The charge carriers behave as massless relativistic particles whose spin and momentum are coupled to

Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells

We show that the quantum spin Hall (QSH) effect, a state of matter with topological properties distinct from those of conventional insulators, can be realized in mercury telluride–cadmium telluride

Chiral topological superconductor from the quantum Hall state

The chiral topological superconductor in two dimensions has a full pairing gap in the bulk and a single chiral Majorana state at the edge. The vortex of the chiral superconducting state carries a