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

Abstract

The existence of the physical elementary energy bands describing the Davydov splitting was demonstrated in the energy spectra of the layered orthorhombic 4 3In Se 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 4 3In Se crystal. The reasons for such a dispersion law to occur in 4 3In Se are discussed as well as its similarity to the dispersion law for holes in the β-InSe crystal under pressure.

Electron-Deformational Phase Transitions in a TlGaSe2Layered Crystal

“…The obtained results indicate an abnormal dispersion of the lowest conduction band in the direction F 1 -Γ -Q 1 which, in our opinion, can be caused by a lowenergy non-parabolicity of the dispersion relation E(k) of this band. A similar situation is observed in the case of several indium selenides [8,15]. Now we estimate a curvature of this dispersion relation near Γ point in the direction Γ -F 1 within the quadratic approximation, by restricting ourselves to a small distance in the k-space.…”

The anisotropic band structure of layered In4Se3(001)

“…In general, our results are comparable with prior calculations. 16,21,31 A. Calculated bulk band structure and density of states…”

Deformation Modulation of Electronic States in Layered Crystals

“…The role of layers, as structural elements bringing forth the adequate spatial dependence of a potential, in forming the peculiarities of electronic properties depends on the structure of the layers and interaction between them. A separate layer in these crystals can have complex multilevel structure which is formed by the intense interatomic interaction [1,2] which leads to a certain isolation of the layer. This property is manifested in the residual interaction between the adjacent layers and conservation of their structure in a wide range of external influences.…”

“…which gives rise to the increase of period (1) or its decrease (2). This property leads to the change in number n and period d z of a deformed crystal over the time by harmonic component of the deforming force that creates the required increments of shifts.…”