title: Reversal of the circular dichroism in angle-resolved photoemission from Bi2Te3.
abstract: The helical Dirac fermions at the surface of topological insulators show a strong circular dichroism which has been explained as being due to either the initial-state spin angular momentum, the initial-state orbital angular momentum, or the handedness of the experimental setup. All of these interpretations conflict with our data from Bi(2)Te(3) which depend on the photon energy and show several sign changes. Our one-step photoemission calculations coupled to ab initio theory confirm the sign change and assign the dichroism to a final-state effect. Instead, the spin polarization of the photoelectrons excited with linearly polarized light remains a reliable probe for the spin in the initial state.
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
authors.forename: M R
authors.initials: MR
authors.lastname: Scholz
authors.forename: J
authors.initials: J
authors.lastname: Sánchez-Barriga
authors.forename: J
authors.initials: J
authors.lastname: Braun
authors.forename: D
authors.initials: D
authors.lastname: Marchenko
authors.forename: A
authors.initials: A
authors.lastname: Varykhalov
authors.forename: M
authors.initials: M
authors.lastname: Lindroos
authors.forename: Yung Jui
authors.initials: YJ
authors.lastname: Wang
authors.forename: Hsin
authors.initials: H
authors.lastname: Lin
authors.forename: A
authors.initials: A
authors.lastname: Bansil
authors.forename: J
authors.initials: J
authors.lastname: Minár
authors.forename: H
authors.initials: H
authors.lastname: Ebert
authors.forename: A
authors.initials: A
authors.lastname: Volykhov
authors.forename: L V
authors.initials: LV
authors.lastname: Yashina
authors.forename: O
authors.initials: O
authors.lastname: Rader