Current-Induced Polarization and the Spin Hall Effect at Room Temperature

TL;DR

This study demonstrates room-temperature electrical spin polarization and the spin Hall effect in ZnSe epilayers, revealing their dependence on doping and temperature, and providing insights into extrinsic spin transport mechanisms.

Contribution

It reports the first observation of current-induced spin polarization and the spin Hall effect in ZnSe at room temperature, with detailed measurements of spin lifetimes and conductivity.

Findings

Spin polarization decreases with doping density.

Spin Hall conductivity estimated at 3 +/- 1.5 Ohms**-1 m**-1/|e| at 20 K.

Effects observed from 10 K to 295 K.

Abstract

Electrically-induced electron spin polarization is imaged in n-type ZnSe epilayers using Kerr rotation spectroscopy. Despite no evidence for an electrically-induced internal magnetic field, current-induced in-plane spin polarization is observed with characteristic spin lifetimes that decrease with doping density. The spin Hall effect is also observed, indicated by an electrically-induced out-of-plane spin polarization with opposite sign for spins accumulating on opposite edges of the sample. The spin Hall conductivity is estimated as 3 +/- 1.5 Ohms**-1 m**-1/|e| at 20 K, which is consistent with the extrinsic mechanism. Both the current-induced spin polarization and the spin Hall effect are observed at temperatures from 10 K to 295 K.