Photoemission of Bi2Se3 with Circularly Polarized Light

Author(s)

J. Sanchez-Barriga, A. Varykhalov, J. Braun, S. -Y. Xu, N. Alidoust, O. Kornilov, J. Minar, Kerstin Hummer, G. Springholz, G. Bauer, R. Schumann, L. V. Yashina, H. Ebert, M. Z. Hasan, O. Rader

Abstract

Topological insulators are characterized by Dirac-cone surface states

with electron spins locked perpendicular to their linear momenta. Recent

theoretical and experimental work implied that this specific spin

texture should enable control of photoelectron spins by circularly

polarized light. However, these reports questioned the so far accepted

interpretation of spin-resolved photoelectron spectroscopy. We solve

this puzzle and show that vacuum ultraviolet photons (50–70 eV) with

linear or circular polarization indeed probe the initial-state spin

texture of Bi2Se3

while circularly polarized 6-eV low-energy photons flip the electron

spins out of plane and reverse their spin polarization, with its sign

determined by the light helicity. Our photoemission calculations, taking

into account the interplay between the varying probing depth,

dipole-selection rules, and spin-dependent scattering effects involving

initial and final states, explain these findings and reveal proper

conditions for light-induced spin manipulation. Our results pave the way

for future applications of topological insulators in optospintronic

devices.

Organisation(s)

Computational Materials Physics

External organisation(s)

Anuchin Research Institute and Museum of Anthropology, Helmholtz-Zentrum Berlin für Materialien und Energie, Princeton University, Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Johannes Kepler Universität Linz, Ludwig-Maximilians-Universität München, Technische Universität München

Journal

Physical Review X

Volume

No. of pages

ISSN

2160-3308

DOI

https://doi.org/10.1103/PhysRevX.4.011046

Publication date

03-2014

Peer reviewed

Yes

Austrian Fields of Science 2012

103009 Solid state physics, 103015 Condensed matter, 103025 Quantum mechanics, 103036 Theoretical physics

Keywords

Portal url

https://ucrisportal.univie.ac.at/en/publications/96d7f4fa-8451-4b07-a08d-f59514b0f44b