Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: Poster Session III (Solid-liquid interfaces; Scanning probe and other methods; Electronic structure theory; Spin-orbit interaction)
O 58.26: Poster
Mittwoch, 13. März 2013, 18:15–21:45, Poster B1
Unoccupied Surface States of Si(111)(√3×√3)R30∘-Bi — •F. Rühl1, D. Niesner1, Th. Fauster1, P. Sessi2, M. Bode2, M. Trioni3, S. Achilli3, G. Bihlmayer4, and E. V. Chulkov5 — 1Universität Erlangen-Nürnberg, Staudtstr. 7, D-91058 Erlangen, Germany — 2Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — 3Dipartimento di Scienza dei Materiali and CNISM, Universitá degli Studi di Milano-Bicocca, Via Cozzi 53, 20125 Milano, Italy — 4Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany — 5Donostia International Physics Center, 20018 San Sebastián, Basque Country, Spain
The (√3×√3)R30∘-reconstructed trimer phase Bi on Si(111) shows giant Rashba spin-splitting in UV photoemission [1].
In the present study, the unoccupied states were investigated by monochromatic (hν= 3.1, 4.65 eV) and bichromatic (hν= 1.55+4.65 eV) two-photon-photoemission. From the photon energy and polarization dependence, surface states are identified and a downward dispersing band 3.28 eV above the Fermi level was found. In addition, surface states exist at 2.58 eV and 2.23 eV at the Γ-point and at the M-Point at 2.5 eV. The workfunction is 4.64 eV. The photovoltage for flatband conditions was determined to 70 meV. The Fermi level is located 0.22 eV above the valence band maximum. A long-lived feature with a lifetime >15 ps was identified at 0.73 eV.
The results are compared with scanning tunneling spectroscopy data and density functional theory calculations.
[1] K. Sakomoto et al., Phys. Rev. Lett. 103, 156801 (2009)