title: Dirac cone with helical spin polarization in ultrathin α-Sn(001) films.
abstract: Spin-split two-dimensional electronic states have been observed on ultrathin Sn(001) films grown on InSb(001) substrates. Angle-resolved photoelectron spectroscopy (ARPES) performed on these films revealed Dirac-cone-like linear dispersion around the Γ¯ point of the surface Brillouin zone, suggesting nearly massless electrons belonging to 2D surface states. The states disperse across a band gap between bulklike quantum well states in the films. Moreover, both circular dichroism of ARPES and spin-resolved ARPES studies show helical spin polarization of the Dirac-cone-like surface states, suggesting a topologically protected character as in a bulk topological insulator (TI). These results indicate that a quasi-3D TI phase can be realized in ultrathin films of zero-gap semiconductors.
authors: Synchrotron SOLEIL, Saint-Aubin-BP 48, F-91192 Gif sur Yvette, France.
authors: Yoshiyuki
authors: Y
authors: Ohtsubo
authors: Patrick
authors: P
authors: Le Fèvre
authors: François
authors: F
authors: Bertran
authors: Amina
authors: A
authors: Taleb-Ibrahimi