Regensburg 2004 – scientific programme
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M: Metallphysik
M 5: Elektronische Eigenschaften
M 5.3: Talk
Monday, March 8, 2004, 12:15–12:30, H4
Initial and final state band contributions in angle resolved photoemission spectra of Bi(111) — •Christian Ast1,2 and Hartmut Höchst1 — 1Synchrotron Radiation Center, University of Wisconsin-Madison, Stoughton, WI, USA — 2Max-Planck-Institut für Festkörperforschung, Stuttgart
Establishing the bulk valence band dispersion Ei(k) from angle resolved photoemission spectra is still an ongoing challenge since the final state bands Ef(k) are generally not known. However, using a broad range of photon energies the measurements extend over several bulk Brillouin zones which can then be used to extract information about the valence band states. An analysis is presented in which the final and initial state dispersion along ΓT is extracted from photoemission spectra of Bi(111). We will show that the free electron final state (FEFS) model is valid above 60 eV. For lower photon energies, we establish an energy dependent extension of the FEFS’s. Because of direct and umklapp transitions into multiple final states we observe emission gaps indicating avoided crossings in certain branches of the final state bands. Once the origin of these additional features is identified, the true bulk valence band dispersion can be established.