Role of Spin Hall Effect in the Topological Side Surface Conduction

Jekwan Lee; Sangwan Sim; Soohyun Park; Chihun In; Seungwan Cho; Seungmin Lee; Soonyoung Cha; Sooun Lee; Hoil Kim; Jehyun Kim; Wooyoung Shim; Jun Sung Kim; Dohun Kim; Hyunyong Choi

doi:10.1021/acsphotonics.8b00592

Role of Spin Hall Effect in the Topological Side Surface Conduction

Jekwan Lee, Sangwan Sim, Soohyun Park, Chihun In, Seungwan Cho, Seungmin Lee, Soonyoung Cha, Sooun Lee, Hoil Kim, Jehyun Kim, Wooyoung Shim, Jun Sung Kim, Dohun Kim, Hyunyong Choi

Research output: Contribution to journal › Article › peer-review

10 Citations (Scopus)

Abstract

The nature of spin transport in the bulk and side surface of three-dimensional topological insulator thin film geometry is a relatively unexplored subject, compared to the extensively studied top and bottom surface states. Here we employ time- and space-resolved helicity-dependent photocurrent measurements to investigate the effect of optically excited bulk carriers on the spin-polarized topological side surface conduction. Time-resolved femtosecond double-pulse excitation reveals that the spin current toward the side surface arises from the bulk-originated spin Hall effect (SHE), whose microscopic origin is governed by an Elliott-Yafet-type spin relaxation mechanism via an extrinsic side jump process. Bias- and temperature-dependent measurements further confirm that the spin scattering in Bi₂Se₃ has multiple sources including impurity and electron-phonon scattering. The SHE-assisted side surface spin conduction shows an exceptionally high charge-to-spin conversion efficiency of 35% at 77 K, which may offer new spintronic applications of topological insulators such as spin-orbit torque or spin-flip controlled light-emitting devices.

Original language	English
Pages (from-to)	3347-3352
Number of pages	6
Journal	ACS Photonics
Volume	5
Issue number	8
DOIs	https://doi.org/10.1021/acsphotonics.8b00592
Publication status	Published - 2018 Aug 15

Bibliographical note

Funding Information:
J.L., S.S., S.P., S.C., S.L, C.I., S.C., and H.C. were supported by the National Research Foundation of Korea (NRF) through the government of Korea (MSIP) (grant nos. NRF-2016R1A4A1012929 and NRF-2015R1A2A1A10052520) and the Global Frontier Program (grant no. 2014M3A6B3063709). H.K. and J.S.K. were supported by SRC Center for Topological Matter (grant no. 2011-0030785) and Max-Plank POSTECH/ KOREA Research Initiative (grant no. 2016K1A4A4A01922028). J.K. and D.L. were supported by the Basic Science Research Program through the NRF funded by MSIP (grant no. NRF-2015R1C1A1A02037430).

Publisher Copyright:
© 2018 American Chemical Society.

All Science Journal Classification (ASJC) codes

Biotechnology
Electronic, Optical and Magnetic Materials
Atomic and Molecular Physics, and Optics
Electrical and Electronic Engineering

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10.1021/acsphotonics.8b00592

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@article{b907a4b3b9934c7c8e4ba547af3e1d20,

title = "Role of Spin Hall Effect in the Topological Side Surface Conduction",

abstract = "The nature of spin transport in the bulk and side surface of three-dimensional topological insulator thin film geometry is a relatively unexplored subject, compared to the extensively studied top and bottom surface states. Here we employ time- and space-resolved helicity-dependent photocurrent measurements to investigate the effect of optically excited bulk carriers on the spin-polarized topological side surface conduction. Time-resolved femtosecond double-pulse excitation reveals that the spin current toward the side surface arises from the bulk-originated spin Hall effect (SHE), whose microscopic origin is governed by an Elliott-Yafet-type spin relaxation mechanism via an extrinsic side jump process. Bias- and temperature-dependent measurements further confirm that the spin scattering in Bi2Se3 has multiple sources including impurity and electron-phonon scattering. The SHE-assisted side surface spin conduction shows an exceptionally high charge-to-spin conversion efficiency of 35% at 77 K, which may offer new spintronic applications of topological insulators such as spin-orbit torque or spin-flip controlled light-emitting devices.",

author = "Jekwan Lee and Sangwan Sim and Soohyun Park and Chihun In and Seungwan Cho and Seungmin Lee and Soonyoung Cha and Sooun Lee and Hoil Kim and Jehyun Kim and Wooyoung Shim and Kim, {Jun Sung} and Dohun Kim and Hyunyong Choi",

note = "Funding Information: J.L., S.S., S.P., S.C., S.L, C.I., S.C., and H.C. were supported by the National Research Foundation of Korea (NRF) through the government of Korea (MSIP) (grant nos. NRF-2016R1A4A1012929 and NRF-2015R1A2A1A10052520) and the Global Frontier Program (grant no. 2014M3A6B3063709). H.K. and J.S.K. were supported by SRC Center for Topological Matter (grant no. 2011-0030785) and Max-Plank POSTECH/ KOREA Research Initiative (grant no. 2016K1A4A4A01922028). J.K. and D.L. were supported by the Basic Science Research Program through the NRF funded by MSIP (grant no. NRF-2015R1C1A1A02037430). Publisher Copyright: {\textcopyright} 2018 American Chemical Society.",

year = "2018",

month = aug,

day = "15",

doi = "10.1021/acsphotonics.8b00592",

language = "English",

volume = "5",

pages = "3347--3352",

journal = "ACS Photonics",

issn = "2330-4022",

publisher = "American Chemical Society",

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T1 - Role of Spin Hall Effect in the Topological Side Surface Conduction

AU - Lee, Jekwan

AU - Sim, Sangwan

AU - Park, Soohyun

AU - In, Chihun

AU - Cho, Seungwan

AU - Lee, Seungmin

AU - Cha, Soonyoung

AU - Lee, Sooun

AU - Kim, Hoil

AU - Kim, Jehyun

AU - Shim, Wooyoung

AU - Kim, Jun Sung

AU - Kim, Dohun

AU - Choi, Hyunyong

N1 - Funding Information: J.L., S.S., S.P., S.C., S.L, C.I., S.C., and H.C. were supported by the National Research Foundation of Korea (NRF) through the government of Korea (MSIP) (grant nos. NRF-2016R1A4A1012929 and NRF-2015R1A2A1A10052520) and the Global Frontier Program (grant no. 2014M3A6B3063709). H.K. and J.S.K. were supported by SRC Center for Topological Matter (grant no. 2011-0030785) and Max-Plank POSTECH/ KOREA Research Initiative (grant no. 2016K1A4A4A01922028). J.K. and D.L. were supported by the Basic Science Research Program through the NRF funded by MSIP (grant no. NRF-2015R1C1A1A02037430). Publisher Copyright: © 2018 American Chemical Society.

PY - 2018/8/15

Y1 - 2018/8/15

N2 - The nature of spin transport in the bulk and side surface of three-dimensional topological insulator thin film geometry is a relatively unexplored subject, compared to the extensively studied top and bottom surface states. Here we employ time- and space-resolved helicity-dependent photocurrent measurements to investigate the effect of optically excited bulk carriers on the spin-polarized topological side surface conduction. Time-resolved femtosecond double-pulse excitation reveals that the spin current toward the side surface arises from the bulk-originated spin Hall effect (SHE), whose microscopic origin is governed by an Elliott-Yafet-type spin relaxation mechanism via an extrinsic side jump process. Bias- and temperature-dependent measurements further confirm that the spin scattering in Bi2Se3 has multiple sources including impurity and electron-phonon scattering. The SHE-assisted side surface spin conduction shows an exceptionally high charge-to-spin conversion efficiency of 35% at 77 K, which may offer new spintronic applications of topological insulators such as spin-orbit torque or spin-flip controlled light-emitting devices.

AB - The nature of spin transport in the bulk and side surface of three-dimensional topological insulator thin film geometry is a relatively unexplored subject, compared to the extensively studied top and bottom surface states. Here we employ time- and space-resolved helicity-dependent photocurrent measurements to investigate the effect of optically excited bulk carriers on the spin-polarized topological side surface conduction. Time-resolved femtosecond double-pulse excitation reveals that the spin current toward the side surface arises from the bulk-originated spin Hall effect (SHE), whose microscopic origin is governed by an Elliott-Yafet-type spin relaxation mechanism via an extrinsic side jump process. Bias- and temperature-dependent measurements further confirm that the spin scattering in Bi2Se3 has multiple sources including impurity and electron-phonon scattering. The SHE-assisted side surface spin conduction shows an exceptionally high charge-to-spin conversion efficiency of 35% at 77 K, which may offer new spintronic applications of topological insulators such as spin-orbit torque or spin-flip controlled light-emitting devices.

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U2 - 10.1021/acsphotonics.8b00592

DO - 10.1021/acsphotonics.8b00592

M3 - Article

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EP - 3352

JO - ACS Photonics

JF - ACS Photonics

IS - 8

ER -

Role of Spin Hall Effect in the Topological Side Surface Conduction

Abstract

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