Valence-band-structure determination of InSb by angle-resolved photoemission

Angle-resolved photoemission with synchrotron radiation was used for an experimental determination of the valence-band structure of InSb along the high-symmetry directions of the bulk Brillouin zone. Normal-emission photoelectron spectra from the (110), (100), and (111) crystal faces exhibit peaks which show dispersion with photon energy. They are interpreted in terms of direct transitions to a free-electron-like final band. The experimental band structure is in general agreement with calculated bands, but there are deviations on the order of 1 eV at several critical points. The justification for the use of a parabolic final band is discussed, and experimental tests for its validity are described.