Electrical detection of spin-polarized current in topological insulator Bi1.5Sb0.5Te1.7Se1.3

TL;DR

This study demonstrates the electrical detection of spin-polarized currents in a topological insulator, revealing non-local spin transport and providing insights into spin polarization at the surface states for spintronics.

Contribution

It presents a novel experimental approach to detect and analyze spin-polarized currents in a bulk insulating topological insulator using spin potentiometric measurements.

Findings

Detection of spin-polarized current in Bi1.5Sb0.5Te1.7Se1.3

Observation of non-local spin-polarized current

Higher spin-polarization ratio in non-local current

Abstract

Spin-momentum locked (SML) topological surface state (TSS) provides exotic properties for spintronics applications. The spin-polarized current, which emerges owing to the SML, can be directly detected by performing spin potentiometric measurement. We observed spin-polarized current using a bulk insulating topological insulator (TI), Bi1.5Sb0.5Te1.7Se1.3, and Co as the ferromagnetic spin probe. The spin voltage was probed with varying the bias current, temperature, and gate voltage. Moreover, we observed non-local spin-polarized current, which is regarded as a distinguishing property of TIs. The spin-polarization ratio of the non-local current was larger than that of the local current. These findings could reveal a more accurate approach to determine spin-polarization ratio at the TSS.