Anomalous thermoelectric Hall response of interacting 2D Dirac fermions

TL;DR

This paper investigates the anomalous thermoelectric Hall response of 2D massive Dirac fermions with electron-electron interactions, revealing unexpected non-vanishing behavior at zero temperature due to nonlocal effects in quantum field theory.

Contribution

It provides a simple formula for magnetization in interacting Dirac fermions and uncovers non-vanishing thermoelectric Hall response at zero temperature.

Findings

Magnetization is described by a simple formula for arbitrary interactions.

Subtracting magnetization currents does not nullify the Hall coefficient at zero temperature.

Nonlocality in quantum field theory affects infrared physics and response functions.

Abstract

We study the anomalous thermoelectric Hall response of two-dimensional massive Dirac fermions to first order in the electron-electron interaction. We compute both the Nernst response to a Luttinger-type gravitational potential and the particle magnetization, the latter being required to remove spurious non-transport contributions. We show that, for arbitrary interactions, the magnetization is described by a remarkably simple formula. Surprisingly, and contrary to expectations, subtracting the magnetization currents does not make the thermoelectric Hall coefficient vanish in the zero-temperature limit. We attribute this to violation of locality on the smallest length scales, which is inevitable in a quantized field theory, that happens to manifest itself in infrared physics.