Spin Nernst effect and Nernst effect in two-dimensional electron systems

TL;DR

This paper investigates the Nernst and spin Nernst effects in a two-dimensional electron system with Rashba spin-orbit interaction under a magnetic field, revealing how these effects depend on system parameters and disorder.

Contribution

It provides a detailed analysis of how Rashba spin-orbit interaction influences the Nernst and spin Nernst effects in a mesoscopic device, highlighting the emergence of oscillatory structures and sensitivity to sample details.

Findings

Nernst coefficient peaks at Landau levels without SOI.

Spin Nernst effect appears and oscillates with SOI.

Nernst effect persists under strong disorder, unlike spin Nernst.

Abstract

We study the Nernst effect and the spin Nernst effect, that a longitudinal thermal gradient induces a transverse voltage and a spin current. A mesoscopic four-terminal cross-bar device having the Rashba spin-orbit interaction (SOI) under a perpendicular magnetic field is considered. For zero SOI, the Nernst coefficient peaks when the Fermi level crosses the Landau Levels. In the presence of the SOI, the Nernst peaks split, and the spin Nernst effect appears and exhibits a series of oscillatory structures. The larger SOI is or the weaker magnetic field is, the more pronounced the spin Nernst effect is. The results also show that the Nernst and spin Nernst coefficients are sensitive to the detailed characteristics of the sample and the contacts. In addition, the Nernst effect is found to survive in strong disorder than the spin Nernst effect does.