Investigation of the electronic structure of the SbSeI cluster

Abstract

The energy levels of valence bands (VBs) and core levels (CLs) of SbSeI single crystals have been investigated theoretically. A molecular model of the SbSeI crystal was used for the calculations of VBs and CLs by the Hartree -Fock method (UHF). This molecular cluster consisting of 20 molecules was used for calculations of the total and of the averaged density of states including atom vibrations. The averaged total density of states is more similar to the experimental X-ray photoelectron spectra (XPS). The cluster-model calculations showed that the splitting of the CLs in SbSeI may be caused by photoelectron emission from the atoms at the surface which are in a different valence state.

Investigation of the electronic structure of the SbSeBr cluster

“…The spectrum of total density of states of SbSeBr cluster differs from experimental X-ray photoelectron spectrum (XPS) of A 5 B 6 C 7 -type crystals. The spectrum of averaged total density of states of SbSeBr cluster containing all normal modes of oscillation is more similar to the experimental XPS of A 5 B 6 C 7 -type crystals. The comparison of results clarifies that atomic vibrations are one of possible reasons for the smoother appearance of the experimental XPS.…”

“…The UHF method as well as the binding energy calculations is described in [5,6]. The authors of work [7] found that DFT (B3LYP functional) method provide a rather accurate description of the band gap and electronic structure of semiconductors.…”

“…A great interest in A 5 B 6 C 7 -type ferroelectrics is caused by the fact that they possess semiconductor properties [1,2]. These ferroelectrics are characterized by a number of unique properties, e.g.…”

“…Such a combination of unique properties opens up wide possibilities to employ it in practice. Besides the practical use, A 5 B 6 C 7 -type crystals are interesting objects of fundamental research. There is a very strong electron-phonon interaction in A 5 B 6 C 7 -type crystals, which affects density of states of VB and also optical and electrical properties.…”

“…We provide a theoret-ical investigation of the electronic structure, the influence of atomic vibration on electronic structure of VB using Unrestricted Hartree -Fock (UHF) and Density Functional Theory (DFT) methods. The theoretical total-and -density of states (total-DOS, -DOS (l-DOS is a sum of s-DOS and p-DOS)) of VB are compared with the experimental X-ray photoemission spectra (XPS) of A 5 B 6 C 7 -type crystals. We present the results of our theoretical investigations in the following sections: Section 2 -the methods for investigation of the electronic structure of molecular cluster.…”