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Fig. 2: Comparison of the experimental initial state bulk band structure of Bi along
the T direction with various model calculations.
Furthermore, scattering events can play a significant role in the interpretation of
photoemission spectra. They lead to various phenomena that can be observed in the
photoemission spectra. It has been shown for bismuth that scattering events induce loss features
in the 5d-core level spectra [2], which can be associated with interband transitions inside the
crystal. In the normal emission spectra we present here secondary cone emission features, which
result from transitions involving reciprocal lattice vectors not parallel to the normal emission
direction, can be observed. For these features to be observed in the normal emission spectra the
photoelectrons need to be scattered back into the normal emission direction. We show that for a
complete data analysis secondary cone emission phenomena have to be included. The presence
of secondary cone emission features in the spectra clearly shows the significance of scattering
phenomena in photoemission spectra of bismuth.
Figure 2 shows the extracted initial state bands (black lines) in comparison with a third
neighbor tight-binding calculation [3], as well as two first principle calculations [4, 5] (dotted
lines). The agreement in the dispersion is mostly qualitatively. The tight binding calculation has
difficulties reproducing the dispersion of the middle band, whereas the calculation by Gonze [4]
shows the best agreement with the experimental initial state bands.
[1] G. Jezequel, J. Thomas, and I. Pollini, Phys. Rev. B 56, 6620 (1997)
[2] C. R. Ast and H. Höchst, Phys. Rev. Lett. in press (2003).
[3] Y. Liu and R. E. Allen, Phys. Rev. B 52, 1566 (1995)
[4] X. Gonze, J.-P. Michenaud, and J.-P. Vigneron, Phys. Rev. B 41, 11827 (1990)
[5] A. B. Shick, J. B. Ketterson, D. L. Novikov, and A. J. Freeman, Phys. Rev. B 60, 15484
(1999)