arXiv subjects

Shou-cheng Zhang

Publications and source records attributed to Shou-cheng Zhang.

3 recordsLinked to original sources

arXiv2016

Anomalous Electron Trajectory in Topological Insulators

We present a general theory about electron orbital motions in topological insulators. An in-plane electric field drives spin-up and spin-down electrons bending to opposite directions, and skipping orbital motions, a counterpart of the integer quantum Hall effect, are formed near the boundary of the sample. The accompanying Zitterbewegung can be found and controlled by tuning external electric fields. Ultrafast flipping electron spin leads to a quantum side jump in the topological insulator, and a snake-orbit motion in two-dimensional electron gas with spin-orbit interactions. This feature provides a way to control electron orbital motion by manipulating electron spin.

cond-mat.mes-hall↗

arXiv2013

Interface-induced Topological Insulator Transition in GaAs/Ge/GaAs Quantum Wells

We demonstrate theoretically that interface engineering can drive Germanium, one of the most commonly-used semiconductors, into topological insulating phase. Utilizing giant electric fields generated by charge accumulation at GaAs/Ge/GaAs opposite semiconductor interfaces and band folding, the new design can reduce the sizable gap in Ge and induce large spin-orbit interaction, which lead to a topological insulator transition. Our work provides a new method on realizing TI in commonly-used semiconductors and suggests a promising approach to integrate it in well developed semiconductor electronic devices.

cond-mat.mes-hall↗

arXiv2003

Exact SO(5) Symmetry in spin 3/2 fermionic system

The spin 3/2 fermion models with contact interactions have a {\it generic} SO(5) symmetry without any fine-tuning of parameters. Its physical consequences are discussed in both the continuum and lattice models. A Monte-Carlo algorithm free of the sign problem at any doping and lattice topology is designed when the singlet and quintet interactions satisfy $U_0\le U_2\le -{3\over5} U_0 (U_0\le 0)$, thus making it possible to study different competing orders with high numerical accuracy. This model can be accurately realized in ultra-cold atomic systems.

cond-mat.str-el↗