Prediction of flatness-driven quantum spin Hall effect in functionalized germanene and stanene

2016 ◽  
Vol 18 (40) ◽  
pp. 28134-28139 ◽  
Author(s):  
Run-wu Zhang ◽  
Wei-xiao Ji ◽  
Chang-wen Zhang ◽  
Ping Li ◽  
Pei-ji Wang
Keyword(s):  
Hall Effect ◽  
First Principles ◽  
Quantum Spin ◽  
Spin Hall Effect ◽  
First Principles Calculations ◽  
Quantum Spin Hall Effect ◽  
Chemical Functionalization ◽  
Quantum Spin Hall

We used first-principles calculations to predict a class of new QSH phases for f-Ge(Sn)X2 films, which are useful for applications because of not only their sizable nontrivial bulk gaps, but also the tunability of the QSH states by chemical functionalization.

Quantum spin Hall effect in two-dimensional hydrogenated SnPb alloy films

2018 ◽  
Vol 20 (14) ◽  
pp. 9610-9615
Author(s):  
Miaojuan Ren ◽  
Min Yuan ◽  
Xinlian Chen ◽  
Weixiao Ji ◽  
Ping Li ◽  
...  
Keyword(s):  
Hall Effect ◽  
First Principles ◽  
Quantum Spin ◽  
Spin Hall Effect ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Band Structures ◽  
Alloy Films ◽  
Quantum Spin Hall Effect ◽  
Quantum Spin Hall

Using first-principles calculations, we studied the geometric and band structures of 20 possible configurations of buckled hydrogenated SnPb alloy (SnxPb8−xH8) films.

scholarly journals Tunable quantum spin Hall effect via strain in two-dimensional arsenene monolayer

2016 ◽  
Vol 49 (5) ◽  
pp. 055305 ◽  
Author(s):  
Ya-ping Wang ◽  
Chang-wen Zhang ◽  
Wei-xiao Ji ◽  
Run-wu Zhang ◽  
Ping Li ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Spin ◽  
Spin Hall Effect ◽  
Two Dimensional ◽  
Quantum Spin Hall Effect ◽  
Quantum Spin Hall

EDGE MAGNETISM AND QUANTUM SPIN HALL EFFECT IN ZIGZAG GRAPHENE NANORIBBON

2013 ◽  
Vol 27 (15) ◽  
pp. 1362011 ◽  
Author(s):  
JUN-WON RHIM ◽  
KYUNGSUN MOON
Keyword(s):  
Electric Field ◽  
Hall Effect ◽  
Graphene Nanoribbon ◽  
Quantum Spin ◽  
Spin Hall Effect ◽  
Nonmonotonic Dependence ◽  
Quantum Spin Hall Effect ◽  
Edge Spin ◽  
Edge Band ◽  
Quantum Spin Hall

We present here a brief review on the remarkable consequences of the flat bands formed at the edges of the Zigzag graphene nanoribbon (ZGNR). The inclusion of the on-site Coulomb interaction is shown to induce the edge spin ferromagnetism, whose spin stiffness demonstrates a nonmonotonic dependence on the lateral electric field. The critical electric field strength corresponds to that of the insulator to half-metal transition. The inclusion of the spin–orbit coupling (SOC) has been believed to generate the quantum spin Hall effect (QSHE) guiding into the interesting new field of topological insulator. By carefully investigating the SOC near the edge, we have shown that the additional σ-edge band gives a marginal perturbation and hence the existence of the QSHE depends on the coupling strength between the π-edge bands and the σ-edge band. We demonstrate that for the charge neutral ZGNR, the QSHE does not occur in the pristine ZGNR, while the hydrogen passivation along the edge may recover the expected feature of the QSHE.

scholarly journals A New Approach to Transport Coefficients in the Quantum Spin Hall Effect

2020 ◽  
Author(s):  
Giovanna Marcelli ◽  
Gianluca Panati ◽  
Stefan Teufel
Keyword(s):  
Hall Effect ◽  
Constant Electric Field ◽  
Transport Coefficients ◽  
Spin Current ◽  
Spin Operator ◽  
Quantum Spin ◽  
Spin Hall Effect ◽  
Current Operator ◽  
Quantum Spin Hall Effect ◽  
Quantum Spin Hall

AbstractWe investigate some foundational issues in the quantum theory of spin transport, in the general case when the unperturbed Hamiltonian operator $$H_0$$ H 0 does not commute with the spin operator in view of Rashba interactions, as in the typical models for the quantum spin Hall effect. A gapped periodic one-particle Hamiltonian $$H_0$$ H 0 is perturbed by adding a constant electric field of intensity $$\varepsilon \ll 1$$ ε ≪ 1 in the j-th direction, and the linear response in terms of a S-current in the i-th direction is computed, where S is a generalized spin operator. We derive a general formula for the spin conductivity that covers both the choice of the conventional and of the proper spin current operator. We investigate the independence of the spin conductivity from the choice of the fundamental cell (unit cell consistency), and we isolate a subclass of discrete periodic models where the conventional and the proper S-conductivity agree, thus showing that the controversy about the choice of the spin current operator is immaterial as far as models in this class are concerned. As a consequence of the general theory, we obtain that whenever the spin is (almost) conserved, the spin conductivity is (approximately) equal to the spin-Chern number. The method relies on the characterization of a non-equilibrium almost-stationary state (NEASS), which well approximates the physical state of the system (in the sense of space-adiabatic perturbation theory) and allows moreover to compute the response of the adiabatic S-current as the trace per unit volume of the S-current operator times the NEASS. This technique can be applied in a general framework, which includes both discrete and continuum models.

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