Anomalous Electron Trajectory in Topological Insulators

TL;DR

This paper develops a comprehensive theory describing how electron trajectories in topological insulators are influenced by electric fields, revealing controllable spin-dependent orbital motions and novel phenomena like Zitterbewegung and quantum side jumps.

Contribution

It introduces a new theoretical framework for electron orbital dynamics in topological insulators, highlighting spin-controlled orbital motions and related quantum effects.

Findings

Spin-up and spin-down electrons bend in opposite directions under electric fields.

Zitterbewegung can be controlled via external electric fields.

Ultrafast spin flips cause quantum side jumps and snake-orbit motions.

Abstract

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.