Optical visualization of the enhanced spin Hall effect in bismuth doped silicon

TL;DR

This paper demonstrates direct visualization of the enhanced spin Hall effect in bismuth-doped silicon at room temperature using helicity-dependent photovoltage measurements, revealing significant spin accumulation.

Contribution

It introduces a novel optical visualization method for the spin Hall effect in Bi-doped silicon, showing a substantial enhancement over traditional materials.

Findings

HDP signals indicate clear spin accumulation at Si edges

Bi-doped Si shows over two orders of magnitude larger signals than platinum

Negligible signals observed in phosphorus-doped Si

Abstract

Direct visualizations of spin accumulation due to the enhanced spin Hall effect (SHE) in bismuth (Bi) - doped silicon (Si) at room temperature are realized by using helicity-dependent photovoltage (HDP) measurements. Under application of a dc current to the Bi-doped Si, clear helicity-dependent photovoltages are detected at the edges of the Si channel, indicating a perpendicular spin accumulation due to the SHE. In contrast, the HDP signals are negligibly small for phosphorus-doped Si. Compared to a platinum channel, which has a large spin Hall angle, more than two-orders of magnitude larger HDP signals are obtained in the Bi-doped Si.