Current-induced nuclear spin polarization in (Bi 1-x Sb x)2 Te 3

Sofie Kölling, A. Mert Bozkurt, Stijn Roelant de Wit, Inanc Adagideli, A. Brinkman

Research output: Contribution to conferencePosterAcademic

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Abstract

Three-dimensional topological insulators (3DTIs) host conducting surface states, while the bulk remains insulating. These surface states are spin-momentum locked, which opens the road to spintronic applications. We investigate the hyperfine interaction between spin-momentum locked electrons and nuclear spins. A DC source-drain bias implies a nonzero electron spin polarization, which is transfered to a nonzero nuclear spin polarization via spin-flip interactions. Inversely, thermal relaxation of a nonzero nuclear spin polarization drives a charge current. This shows as an inductive current, observable at timescales comparable to the nuclear spin-flip rate. At DC timescales, the nonzero nuclear polarization is expected to affect resistance as a function of applied bias. Moreover, the additional in-plane magnetic field stemming from nuclear polarization is expected to affect phase coherence lengths.

We search for signatures of current-induced nuclear polarization in the 3DTI (Bi 1-x Sb x)2 Te 3 (BST). The high nuclear spin abundancy makes this an excellent candidate material. BST thin-films are deposited by molecular beam epitaxy, which allows for tuning the position of Fermi level and Dirac point within the bulk band gap. The experiments focus on probing effects of non-zero nuclear polarization using DC signals. However, careful consideration is required to distinguish signatures of other effects, such as electron-electron interactions and Joule heating.
Original languageEnglish
Publication statusPublished - 23 Jan 2024
EventNWO Physics 2024 - Veldhoven, Netherlands
Duration: 23 Jan 202424 Jan 2024

Conference

ConferenceNWO Physics 2024
Country/TerritoryNetherlands
CityVeldhoven
Period23/01/2424/01/24

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