Origin of spin-polarized photocurrents in the topological surface states of Bi2 Se3

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23640%2F18%3A43952820" target="_blank" >RIV/49777513:23640/18:43952820 - isvavai.cz</a>

Výsledek na webu

<a href="http://hdl.handle.net/11025/30745" target="_blank" >http://hdl.handle.net/11025/30745</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevB.98.155406" target="_blank" >10.1103/PhysRevB.98.155406</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Origin of spin-polarized photocurrents in the topological surface states of Bi2 Se3

Popis výsledku v původním jazyce

For the generation of spin-polarized photocurrents in topological insulators, a coupling between photon angular momentum and electron spin is often assumed. Such a coupling seems to be supported by dichroism reported in E(ky)-intensity maps in photoemission. We show in three dimensional two-photon photoemission and one-step photoemission calculations that the circular dichroism is in fact threefold in E(kx,k y) maps although it may appear antisymmetric in E(ky). The threefold symmetry is inconsistent with the previously assumed coupling between photon momentum and electron’s chiral spin via the orbital momentum. Instead it reflects the surface point group. The only antisymmetric patterns appear in the energy range in which surface and bulk states hybridize. In general, a threefold-symmetric dichroic signal does not support unidirectional photocurrents. Nevertheless, the residual asymmetry of up to 3.5% in our photoemission spectra is compatible with previously observed helicity-dependent photocurrents.

Název v anglickém jazyce

Origin of spin-polarized photocurrents in the topological surface states of Bi2 Se3

Popis výsledku anglicky

For the generation of spin-polarized photocurrents in topological insulators, a coupling between photon angular momentum and electron spin is often assumed. Such a coupling seems to be supported by dichroism reported in E(ky)-intensity maps in photoemission. We show in three dimensional two-photon photoemission and one-step photoemission calculations that the circular dichroism is in fact threefold in E(kx,k y) maps although it may appear antisymmetric in E(ky). The threefold symmetry is inconsistent with the previously assumed coupling between photon momentum and electron’s chiral spin via the orbital momentum. Instead it reflects the surface point group. The only antisymmetric patterns appear in the energy range in which surface and bulk states hybridize. In general, a threefold-symmetric dichroic signal does not support unidirectional photocurrents. Nevertheless, the residual asymmetry of up to 3.5% in our photoemission spectra is compatible with previously observed helicity-dependent photocurrents.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

<a href="/cs/project/EF15_003%2F0000358" target="_blank" >EF15_003/0000358: Výpočetní a experimentální design pokročilých materiálů s novými funkcionalitami</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review B

ISSN

2469-9950

e-ISSN

—

Svazek periodika

98

Číslo periodika v rámci svazku

15

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

7

Strana od-do

"NESTRÁNKOVÁNO"

Kód UT WoS článku

000446820900006

EID výsledku v databázi Scopus

2-s2.0-85054573045