Similarities of the band structure of In4Se3 and InSe under pressure and peculiarities of the creation of the band gap

The existence of the physical elementary energy bands describing the Davydov splitting was demonstrated in the energy spectra of the layered orthorhombic In4Se3 crystal. It was confirmed that the physical elementary energy bands are related to the exactly determined Wyckoff position in the unit cell, where the maximum of the valence electron density is localized. By means of ab initio calculations, the dispersion laws with the low-energy non-parabolicity were obtained for electrons and holes of the In4Se3 crystal. The reasons for such a dispersion law to occur in In4Se3 are discussed as well as its similarity to the dispersion law for holes in the β -InSe crystal under pressure. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)