Undulated 2D materials as a platform for large Rashba spin-splitting and persistent spin-helix states

Fuente: arXiv
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Main Authors: Gupta, Sunny, Mattur, Manoj N., Yakobson, Boris I.
Format: Preprint
Published: 2024
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author Gupta, Sunny
Mattur, Manoj N.
Yakobson, Boris I.
author_facet Gupta, Sunny
Mattur, Manoj N.
Yakobson, Boris I.
contents Materials with large unidirectional Rashba spin-orbit coupling (SOC), resulting in persistent-spin helix states with small spin-precession length, are critical for advancing spintronics. We demonstrate a design principle achieving it through specific undulations of 2D materials. Analytical model and first-principles calculations reveal that bending-induced asymmetric hybridization brings about and even enhances Rashba SOC. Its strength $α_R \propto κ$ (curvature) and shifting electronic levels $Δ\propto κ^2$. Despite the vanishing integral curvature of typical topographies, implying a net-zero Rashba effect, our two-band analysis and electronic structure calculation of a bent 2D MoTe$_2$ show that only an interplay of $α_R$ and $Δ$ modulations results in large unidirectional Rashba SOC with well-isolated states. Their high spin-splitting $\sim 0.16$ eV, and attractively small spin-precession length $\sim 1$ nm, are among the best known. Our work uncovers major physical effects of undulations on Rashba SOC in 2D materials, opening new avenues for using their topographical deformation for spintronics and quantum computing.
format Preprint
id arxiv_https___arxiv_org_abs_2410_16242
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Undulated 2D materials as a platform for large Rashba spin-splitting and persistent spin-helix states
Gupta, Sunny
Mattur, Manoj N.
Yakobson, Boris I.
Materials Science
Mesoscale and Nanoscale Physics
Materials with large unidirectional Rashba spin-orbit coupling (SOC), resulting in persistent-spin helix states with small spin-precession length, are critical for advancing spintronics. We demonstrate a design principle achieving it through specific undulations of 2D materials. Analytical model and first-principles calculations reveal that bending-induced asymmetric hybridization brings about and even enhances Rashba SOC. Its strength $α_R \propto κ$ (curvature) and shifting electronic levels $Δ\propto κ^2$. Despite the vanishing integral curvature of typical topographies, implying a net-zero Rashba effect, our two-band analysis and electronic structure calculation of a bent 2D MoTe$_2$ show that only an interplay of $α_R$ and $Δ$ modulations results in large unidirectional Rashba SOC with well-isolated states. Their high spin-splitting $\sim 0.16$ eV, and attractively small spin-precession length $\sim 1$ nm, are among the best known. Our work uncovers major physical effects of undulations on Rashba SOC in 2D materials, opening new avenues for using their topographical deformation for spintronics and quantum computing.
title Undulated 2D materials as a platform for large Rashba spin-splitting and persistent spin-helix states
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2410.16242