Extrinsic Spin Nernst Effect from First Principles

We present an ab initio description of the thermal transport phenomenon called the spin Nernst effect. It refers to generation of a spin accumulation or a pure spin current transverse to an applied temperature gradient. This is similar to the intensively studied spin Hall effect described by intrinsic and extrinsic mechanisms due to an applied electric field. Analogously, several contributions are present for the spin Nernst effect. Here we investigate the extrinsic skew scattering mechanism which is dominant in the limit of dilute alloys. Our calculations are based on a fully relativistic Korringa-Kohn-Rostoker method and a solution of the linearized Boltzmann equation. As a first application, we consider a Cu host with Au, Ti, and Bi impurities.

Figure 1

The family of the Hall- and Nernst-type effects.

Figure 2

Total LDOS for the Au, Ti, and Bi impurities in a Cu host (upper panel) and $p$ states only (lower panel). The energy interval ($E_{\min },E_{\max }$) is depicted by the vertical lines.

Figure 3

A diagonal component of the thermopower (upper panel) and $yx$ component of the spin Seebeck coefficient (lower panel) for a Cu host with Au, Ti, and Bi impurities.

Figure 4

Spin Nernst conductivity for Au (upper panel), Ti (middle panel), and Bi (lower panel) impurities in a Cu host at an impurity concentration of 1 at. %.