Hexagonal Warping Induced Nonlinear Planar Nernst Effect in Nonmagnetic Topological Insulators

TL;DR

This paper theoretically predicts a nonlinear planar Nernst effect in nonmagnetic topological insulators, driven by hexagonal warping, spin-momentum locking, and magnetic field, with potential implications for thermoelectric applications.

Contribution

It introduces the concept of a nonlinear planar Nernst effect in nonmagnetic topological insulators, highlighting its quantum origin and dependence on magnetic field orientation.

Findings

Nernst current scales quadratically with temperature gradient.

Nernst current scales linearly with magnetic field.

Effect exhibits cosine dependence on magnetic field orientation.

Abstract

We propose theoretically a new effect, i.e. nonlinear planar Nernst effect (NPNE), in nonmagnetic topological insulator (TI) Bi2Te3 in the presence of an in-plane magnetic field. We find that the Nernst current scales quadratically with temperature gradient but linearly with magnetic field and exhibits a cosine dependence of the orientation of the magnetic field with respect to the direction of the temperature gradient. The NPNE has a quantum origin arising from the conversion of a nonlinear transverse spin current to a charge current due to a joint result of hexagonal warping effect, spin-momentum locking, and the time-reversal symmetry breaking induced by the magnetic field.