scholarly journals Inversion-symmetry protected chiral hinge states in stacks of doped quantum Hall layers

2018 ◽  
Vol 98 (24) ◽  
Author(s):  
Sander H. Kooi ◽  
Guido van Miert ◽  
Carmine Ortix
Keyword(s):  
Quantum Hall ◽  
Inversion Symmetry ◽  
Symmetry Protected

scholarly journals Defective edge states and anomalous bulk-boundary correspondence for topological insulators under non-Hermitian similarity transformation

2020 ◽  
Vol 34 (09) ◽  
pp. 2050146
Author(s):  
C. Wang ◽  
X.-R. Wang ◽  
C.-X. Guo ◽  
S.-P. Kou
Keyword(s):  
Chiral Symmetry ◽  
Topological Insulators ◽  
Skin Effect ◽  
Similarity Transformation ◽  
Topological Invariant ◽  
Inversion Symmetry ◽  
Edge States ◽  
Boundary Correspondence ◽  
Zhang Model ◽  
Symmetry Protected

It was known that for non-Hermitian topological systems due to the non-Hermitian skin effect, the bulk-edge correspondence is broken down. In this paper, by using one-dimensional Su–Schrieffer–Heeger model and two-dimensional (deformed) Qi–Wu–Zhang model as examples, the focus is on a special type of non-Hermitian topological system without non-Hermitian skin effect — topological systems under non-Hermitian similarity transformation. In these non-Hermitian systems, the defective edge states and the breakdown of bulk-edge correspondence are discovered. To characterize the topological properties, a new type of inversion symmetry-protected topological invariant — total [Formula: see text] topological invariant — has been introduced. In topological phases, defective edge states appear. With the help of the effective edge Hamiltonian, it was found that the defective edge states are protected by (generalized) chiral symmetry and thus the (singular) defective edge states are unstable against the perturbation breaking the chiral symmetry. In addition, the results are generalized to non-Hermitian topological insulators with inversion symmetry in higher dimensions. This work could help people to understand the defective edge states and the breakdown of bulk-edge correspondence for non-Hermitian topological systems.

scholarly journals Topology- and symmetry-protected domain wall conduction in quantum Hall nematics

2019 ◽  
Vol 100 (16) ◽  
Author(s):  
Kartiek Agarwal ◽  
Mallika T. Randeria ◽  
A. Yazdani ◽  
S. L. Sondhi ◽  
S. A. Parameswaran
Keyword(s):  
Domain Wall ◽  
Quantum Hall ◽  
Symmetry Protected ◽  
Protected Domain

scholarly journals On the matter of topological insulators as magnetoelectrics

2019 ◽  
Vol 6 (4) ◽  
Author(s):  
N. Peter Armitage ◽  
Liang Wu
Keyword(s):  
Topological Insulators ◽  
Chemical Potential ◽  
Quantum Hall ◽  
Real Life ◽  
Electric Polarization ◽  
Inversion Symmetry ◽  
Real Material ◽  
Magnetoelectric Response ◽  
Physical Consequences ◽  
The Right

It has been proposed that topological insulators can be best characterized not as surface conductors, but as bulk magnetoelectrics that – under the right conditions– have a universal quantized magnetoelectric response coefficient \boldsymbol{e^2/2 h}𝐞2/2𝐡. However, it is not clear to what extent these conditions are achievable in real materials that can have disorder, finite chemical potential, residual dissipation, and even inversion symmetry. This has led to some confusion and misconceptions. The primary goal of this work is to illustrate exactly under what real life scenarios and in what context topological insulators can be described as magnetoelectrics. We explore analogies of the 3D magnetoelectric response to electric polarization in 1D in detail, the formal vs. effective polarization and magnetoelectric susceptibility, the \boldsymbol{\frac{1}{2}}12 quantized surface quantum Hall effect, the multivalued nature of the magnetoelectric susceptibility, the role of inversion symmetry, the effects of dissipation, and the necessity for finite frequency measurements. We present these issues from the perspective of experimentalists who have struggled to take the beautiful theoretical ideas and to try to measure their (sometimes subtle) physical consequences in messy real material systems.

scholarly journals Resonant spin Hall conductance in quantum Hall systems lacking bulk and structural inversion symmetry

2005 ◽  
Vol 71 (15) ◽  
Author(s):  
Shun-Qing Shen ◽  
Yun-Juan Bao ◽  
Michael Ma ◽  
X. C. Xie ◽  
Fu Chun Zhang
Keyword(s):  
Quantum Hall ◽  
Inversion Symmetry ◽  
Hall Conductance ◽  
Quantum Hall Systems ◽  
Structural Inversion

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

Phenomena and devices at the quantum scale and the mesoscale

2017 ◽  
Author(s):  
Sandip Tiwari
Keyword(s):  
Coulomb Blockade ◽  
Secure Communication ◽  
Quantum Hall ◽  
Nanoscale Device ◽  
Self Energy ◽  
Stability Diagrams ◽  
Charge Stability ◽  
Bohm Effect ◽  
Aharonov Bohm ◽  
Non Locality

Unique nanoscale phenomena arise in quantum and mesoscale properties and there are additional intriguing twists from effects that are classical in origin. In this chapter, these are brought forth through an exploration of quantum computation with the important notions of superposition, entanglement, non-locality, cryptography and secure communication. The quantum mesoscale and implications of nonlocality of potential are discussed through Aharonov-Bohm effect, the quantum Hall effect in its various forms including spin, and these are unified through a topological discussion. Single electron effect as a classical phenomenon with Coulomb blockade including in multiple dot systems where charge stability diagrams may be drawn as phase diagram is discussed, and is also extended to explore the even-odd and Kondo consequences for quantum-dot transport. This brings up the self-energy discussion important to nanoscale device understanding.

Sign in / Sign up

Export Citation Format

Share Document