Highly efficient spin-to-charge current conversion at room temperature in strained HgTe surface states

TL;DR

This paper demonstrates highly efficient room-temperature spin-to-charge conversion in strained HgTe surface states, attributed to spin momentum locking, with detailed analysis of layer thickness and barrier effects.

Contribution

It reports the first observation of high-efficiency spin-to-charge conversion in strained HgTe at room temperature, highlighting the role of surface states and structural parameters.

Findings

Inverse Edelstein length up to 2.0 nm

Conversion efficiency depends on HgTe layer thickness

Barrier insertion affects spin-to-charge conversion

Abstract

We report the observation of spin-to-charge current conversion in strained mercury telluride at room temperature, using spin pumping experiments. The conversion rates are found to be very high, with inverse Edelstein lengths up to 2.0 +/- 0.5 nm. The influence of the HgTe layer thickness on the conversion efficiency has been studied, as well as the role of a HgCdTe barrier inserted in-between the HgTe and NiFe layers. These measurements, associated to the temperature dependence of the resistivity, allows to ascribe these high conversion rates to the spin momentum locking property of HgTe surface states.