Room-temperature spin thermoelectrics in metallic films

Abstract

Considering metallic films at room temperature, we present the first theoretical study of the spin Nernst and thermal Edelstein effects that takes into account dynamical spin-orbit coupling, i.e., direct spin-orbit coupling with the vibrating lattice (phonons) and impurities. This gives rise to a novel process, namely, a dynamical side-jump mechanism, and to dynamical Elliott-Yafet spin relaxation, never before considered in this context. Both are the high-temperature counterparts of the well-known T = 0 side-jump and Elliott-Yafet, central to the current understanding of the spin Hall, spin Nernst and Edelstein (current-induced spin polarization) effects at low T . We consider the experimentally relevant regime T > T D , with T D the Debye temperature, as the latter is lower than room temperature in transition metals such as Pt, Au and Ta typically employed in spin injection/extraction experiments. We show that the interplay between intrinsic (Bychkov-Rashba type) and extrinsic (dynamical) spin-orbit coupling yields a nonlinear T dependence of the spin Nernst and spin Hall conductivities.

Spin-charge coupled dynamics driven by a time-dependent magnetization

“…(39) and (48), which corresponds to a spatially homogeneous situation. Neglecting terms ∼β 2 s and smaller for the spin-density-dependent contribution, we find…”

“…Such an effective field is taken to be homogeneous across the whole, not necessarily strictly 2D, sample, similar to the case in Refs. [17,39]. The opposite limit of a bulk metal with a sharp δ-like Rashba spin-orbit coupling at the interface has also been considered [21,[40][41][42] and recently discussed in great detail [43,44].…”

Spin Hall Effects Due to Phonon Skew Scattering

“…The T ¼ 0 processes, as well as the dynamical side-jump and Elliott-Yafet processes, have been discussed in Ref. [16]. In particular, skew scattering from impurities is described by the self-energy diagrams of Fig.…”

Spin-charge Coupling Effects in a Two-dimensional Electron Gas

“…This is known as the Edelstein More precisely, we derive s y in terms of a stationary thermal gradient along the x-direction, ∇ x T , in the absence of any additional external fields. 12 However, in an experiment one would still measure an electric field E x due to a gradient in the chemical potential, ∇ x µ, resulting from an imbalance of the charge carriers due to the thermal gradient. For this, we shall first consider the trace of Eq.…”