Spin-selective tunneling from nanowires of the candidate topological Kondo insulator SmB6

TL;DR

This paper investigates spin-selective tunneling in nanowires of the topological Kondo insulator SmB6, revealing spin-polarized current conduction and the temperature-dependent visibility of topological surface states.

Contribution

It introduces a novel tunneling geometry using SmB6 nanowires to probe spin-momentum locking and topological surface states in a topological Kondo insulator.

Findings

Spin-polarized currents are demonstrated in SmB6 nanowires.

Topological surface states vanish above 10 K.

Spin polarization direction is linked to tunneling direction.

Abstract

Incorporating relativistic physics into quantum tunneling can lead to exotic behavior such as perfect transmission via Klein tunneling. Here, we probe the tunneling properties of spin-momentum locked relativistic fermions by designing and implementing a tunneling geometry that utilizes nanowires of the topological Kondo insulator candidate, SmB6. The nanowires are attached to the end of scanning tunneling microscope tips, and used to image the bicollinear stripe spin-order in the antiferromagnet Fe1.03Te with a Neel temperature of ~50 K. The antiferromagnetic stripes become invisible above 10 K concomitant with the suppression of the topological surface states. We further demonstrate that the direction of spin-polarization is tied to the tunneling direction. Our technique establishes SmB6 nanowires as ideal conduits for spin-polarized currents.