Thermoelectric response in nodal-point semimetals

TL;DR

This review explores the thermoelectric properties of nodal-point semimetals, highlighting how scattering mechanisms, anisotropy, and magnetic fields influence thermoelectric responses in 2D and 3D systems.

Contribution

It provides a comprehensive analysis of thermoelectric coefficients considering different scattering mechanisms, anisotropy, and Berry phase effects in nodal-point semimetals.

Findings

Thermoelectric coefficients vary with scattering mechanisms.

Anisotropy significantly affects thermopower.

Exotic behaviors observed in Hall and thermal Hall responses.

Abstract

In this review, the thermoelectric properties in nodal-point semimetals with two bands are discussed. For the two-dimensional (2D) cases, it is shown that the expressions of the thermoelectric coefficients take different values depending on the nature of the scattering mechanism responsible for transport, by considering examples of short-ranged disorder potential and screened charged impurities. An anisotropy in the energy dispersion spectrum invariably affects the thermopower quite significantly, as illustrated by the results for a node of semi-Dirac semimetal and a single valley of graphene. The scenario when a magnetic field of magnitude $B$ is applied perpendicular to the plane of the 2D semimetal is also considered. The computations for three-dimensional (3D) cases necessarily involve the inclusion of nontrivial Berry phase effects. In addition to demonstrating the expressions for the response tensors, the exotic behaviour observed in planar Hall and planar thermal Hall set-ups is also discussed.