Nonstandard electron dynamics in topological insulators subjected to magnetic field: the Berry phase effects

TL;DR

This paper investigates how Berry phase effects alter electron dynamics on the surface of topological insulators in magnetic fields, revealing new phenomena like anomalous velocity and trajectory bending that impact cyclotron resonance.

Contribution

It introduces a modified quasiclassical model accounting for Berry curvature effects and predicts new electron behaviors in topological insulators under magnetic fields.

Findings

Berry curvature induces anomalous velocity in electron trajectories.

Magnetic field causes trajectory bending related to orbital momentum.

Cyclotron resonance conditions are affected by topological order.

Abstract

The quasiclassical dynamics is studied for charge carriers moving on the surface of 3D topological insulator of Bi2Te3 type and subjected to static magnetic field. The effects connected to the symmetry changes of electron isoenergetic surfaces (contours) and to the nonzero Berry curvature are taken into account. It is shown that in contrast to the standard dynamics of the electrons moving in constant and uniform magnetic field along the trajectories defined by the equations E(k)=const and pz=const, here some new effects are arising, being related to both the appearance of the anomalous velocity term proportional to the Berry curvature, and to the trajectory bending related to the additional term for the energy proportional to the orbital momentum of the wavepacket. This should lead to the changes in cyclotron resonance conditions of the surface electrons. Although the time reversal invariance and the topological order are broken in the magnetic field, the investigation of cyclotron resonance allows determining whether this insulator was trivial or nontrivial at zero magnetic field.