Pure spin currents induced by spin-dependent scattering processes in SiGe quantum well structures

TL;DR

This paper demonstrates that spin-dependent electron-phonon interactions in SiGe quantum wells generate pure spin currents, which can be converted into measurable electric currents using magnetic fields, supported by a microscopic theoretical model.

Contribution

It introduces a new mechanism for pure spin current generation via spin-dependent scattering in SiGe structures and provides a microscopic theory aligning with experimental results.

Findings

Spin-dependent electron-phonon interaction causes pure spin currents.

Magnetic fields convert pure spin currents into electric currents.

Theoretical model agrees with experimental data.

Abstract

We show that spin-dependent electron-phonon interaction in the energy relaxation of a two-dimensional electron gas results in equal and oppositely directed currents in the spin-up and spin-down subbands yielding a pure spin current. In our experiments on SiGe heterostructures the pure spin current is converted into an electric current applying a magnetic field that lifts the cancellation of the two partial charge flows. A microscopic theory of this effect, taking account of the asymmetry of the relaxation process, is developed being in a good agreement with the experimental data.