Loading…
Role of Spin Hall Effect in the Topological Side Surface Conduction
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 measu...
Saved in:
Published in: | ACS photonics 2018-08, Vol.5 (8), p.3347-3352 |
---|---|
Main Authors: | , , , , , , , , , , , , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | 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. |
---|---|
ISSN: | 2330-4022 2330-4022 |
DOI: | 10.1021/acsphotonics.8b00592 |