title: Role of spin-orbit coupling and hybridization effects in the electronic structure of ultrathin Bi films.
abstract: The electronic structure of Bi(001) ultrathin films (thickness > or =7 bilayers) on Si(111)-7x7 was studied by angle-resolved photoemission spectroscopy and first-principles calculations. In contrast with the semimetallic nature of bulk Bi, both the experiment and theory demonstrate the metallic character of the films with the Fermi surface formed by spin-orbit-split surface states (SSs) showing little thickness dependence. Below the Fermi level, we clearly detected quantum well states (QWSs) at the M point, which were surprisingly found to be non-spin-orbit split; the films are "electronically symmetric" despite the obvious structural nonequivalence of the top and bottom interfaces. We found that the SSs hybridize with the QWSs near M and lose their spin-orbit-split character.
authors.affiliation: Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hirahara
authors.forename: T
authors.initials: T
authors.lastname: Nagao
authors.forename: I
authors.initials: I
authors.lastname: Matsuda
authors.forename: G
authors.initials: G
authors.lastname: Bihlmayer
authors.forename: E V
authors.initials: EV
authors.lastname: Chulkov
authors.forename: Yu M
authors.initials: YM
authors.lastname: Koroteev
authors.forename: P M
authors.initials: PM
authors.lastname: Echenique
authors.forename: M
authors.initials: M
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Hasegawa