Spin-momentum locking induced non-local voltage in topological insulator nanowire

TL;DR

This study demonstrates that spin-momentum locking in Sb2Te3 topological insulator nanowires leads to distinctive non-local voltage signals, revealing unique spin transport properties driven by strong spin-orbit coupling.

Contribution

It provides experimental evidence of spin-momentum locking effects in topological insulator nanowires through non-local voltage measurements with magnetic tunnel junctions.

Findings

Non-local voltage symmetry depends on magnetic field orientation.

Reversal of all magnetic contacts changes the non-local voltage.

Distinct behavior from conventional spin valves observed.

Abstract

The momentum and spin of charge carriers in the topological insulators are constrained to be perpendicular to each other due to the strong spin-orbit coupling. We have investigated this unique spin-momentum locking property in Sb2Te3 topological insulator nanowires by injecting spin-polarized electrons through magnetic tunnel junction electrodes. Non-local voltage measurements exhibit a symmetry with respect to the magnetic field applied perpendicular to the nanowire channel, which is remarkably different from that of a non-local measurement in a channel that lacks spin-momentum locking. In stark contrast to conventional non-local spin valves, simultaneous reversal of magnetic moments of all magnetic contacts to the Sb2Te3 nanowire alters the non-local voltage. This unusual symmetry is a clear signature of the spin-momentum locking in the Sb2Te3 nanowire surface states.