Intrinsic Spin Transport in a Topological Insulator Thin Film

Fuente: arXiv
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Main Authors: Jois, Sharadh, Stephen, Gregory M., Blumenschein, Nick, Taylor, Patrick J., Hanbicki, Aubrey T., Friedman, Adam L.
Format: Preprint
Published: 2025
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author Jois, Sharadh
Stephen, Gregory M.
Blumenschein, Nick
Taylor, Patrick J.
Hanbicki, Aubrey T.
Friedman, Adam L.
author_facet Jois, Sharadh
Stephen, Gregory M.
Blumenschein, Nick
Taylor, Patrick J.
Hanbicki, Aubrey T.
Friedman, Adam L.
contents Topological insulators (TIs) are intriguing materials for advanced computing applications based on spintronics because they can host robust spin effects. For instance, TIs have intrinsically large spin generation enabled by their large spin-orbit coupling. Furthermore, topological surface states (TSS) with spin-momentum locking and Dirac dispersion lead to long spin diffusion. Future spintronic device technology will require scalable film growth of high-quality material. We grow epitaxial films of Bi$_{1-x}$Sb$_x$Te$_{3-y}$Se$_y$ (BSTS, $x = 0.58, y = 1$) and confirm the gapless band structure with optimal doping using angle-resolved photoelectron spectra. The temperature dependence of longitudinal resistivity shows bulk transport is suppressed as temperature is decreased, and at low temperature surface transport dominates. We evaluate the spin transport properties in BSTS without using ferromagnetic tunnel contacts via a non-local resistance experiment as a function of temperature and applied charge current. As expected, these experiments reveal the necessity of decreasing the bulk conduction to best enhance the spin transport. In the TSS, we find high efficiency of charge-to-spin conversion (spin Hall angle, $θ_{SH} \approx 1$) and spin diffusion over several microns. Further development of high-quality TIs will make them viable candidates for efficient and lossless spintronics.
format Preprint
id arxiv_https___arxiv_org_abs_2503_04962
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Intrinsic Spin Transport in a Topological Insulator Thin Film
Jois, Sharadh
Stephen, Gregory M.
Blumenschein, Nick
Taylor, Patrick J.
Hanbicki, Aubrey T.
Friedman, Adam L.
Mesoscale and Nanoscale Physics
Applied Physics
Topological insulators (TIs) are intriguing materials for advanced computing applications based on spintronics because they can host robust spin effects. For instance, TIs have intrinsically large spin generation enabled by their large spin-orbit coupling. Furthermore, topological surface states (TSS) with spin-momentum locking and Dirac dispersion lead to long spin diffusion. Future spintronic device technology will require scalable film growth of high-quality material. We grow epitaxial films of Bi$_{1-x}$Sb$_x$Te$_{3-y}$Se$_y$ (BSTS, $x = 0.58, y = 1$) and confirm the gapless band structure with optimal doping using angle-resolved photoelectron spectra. The temperature dependence of longitudinal resistivity shows bulk transport is suppressed as temperature is decreased, and at low temperature surface transport dominates. We evaluate the spin transport properties in BSTS without using ferromagnetic tunnel contacts via a non-local resistance experiment as a function of temperature and applied charge current. As expected, these experiments reveal the necessity of decreasing the bulk conduction to best enhance the spin transport. In the TSS, we find high efficiency of charge-to-spin conversion (spin Hall angle, $θ_{SH} \approx 1$) and spin diffusion over several microns. Further development of high-quality TIs will make them viable candidates for efficient and lossless spintronics.
title Intrinsic Spin Transport in a Topological Insulator Thin Film
topic Mesoscale and Nanoscale Physics
Applied Physics
url https://arxiv.org/abs/2503.04962