Seebeck and Nernst effects in topological insulator: the case of strained HgTe

TL;DR

This paper theoretically investigates the thermoelectric properties of strained HgTe topological insulators, revealing significant enhancements in Seebeck and Nernst effects compared to other 2D Dirac materials, with detailed analysis of magnetic field and temperature dependencies.

Contribution

The study develops a Dirac Hamiltonian model for strained HgTe and analyzes its thermoelectric responses, highlighting their remarkable enhancement over similar materials.

Findings

Seebeck and Nernst effects are significantly enhanced in strained HgTe.

Thermoelectric responses depend strongly on magnetic field and temperature.

Compared to graphene and other 2D Dirac materials, HgTe shows superior thermoelectric performance.

Abstract

We theoretically study the thermoelectric transport properties of strained HgTe in the topological insulator phase. We developed a model for the system using a Dirac Hamiltonian including the effect of strain induced by the interface between HgTe and the CdTe substrate. The conductivity tensor was explored assuming the electrons are scattered by charge impurities, while the thermopower tensor was addressed using the Mott relation. Seebeck and Nernst responses exhibit remarkable enhancements in comparison with other two-dimensional Dirac materials, such as graphene, germanane, prosphorene and stanene. The intensity of these termoeletric responses, their dependencies with the external perpendicular magnetic field and temperature are also addressed.