Thermoelectric response of spin polarization in Rashba spintronic systems

TL;DR

This paper investigates the thermoelectric response of spin polarization in Rashba spintronic systems, revealing new behaviors near the band crossing point and highlighting differences from previous relaxation time approximation results.

Contribution

It provides an exact solution for the thermoelectric spin response in 2D Rashba systems, showing breakdown of Mott-like relations near the band crossing point.

Findings

Spin polarization linear in Fermi energy below band crossing

Breakdown of Mott-like relation near band crossing

Temperature-gradient induced spin polarization vanishes at zero temperature

Abstract

Motivated by recent discovery of strongly spin-orbit coupled two-dimensional (2D) electron gas near the surface of Rashba semiconductors BiTeX (X=Cl, Br, I), we calculate thermoelectric responses of spin polarization in 2D Rashba model using an exact solution of the linearized Boltzmann equation for elastic scattering. When the Fermi energy $E_{F}$ lies below the band crossing point we find a non-Edelstein electric-field induced spin polarization which is linear in $E_{F}$. We show that the Mott-like relation between spin polarizations induced by the temperature gradient and electric field breaks down significantly when $E_{F}$ lies in the vicinity of the band crossing point. As the temperature tends to zero, the temperature-gradient induced spin polarization vanishes. These results differ from previous ones obtained by relaxation time approximations.