Modeling the static and dynamic properties of liquid tellurium with an empirical tight-binding Hamiltonian

Abstract

The structure and dynamics of liquid and supercooled tellurium are investigated using molecular dynamics and an empirical tight-binding Hamiltonian model designed to reproduce ab initio cohesive energies and band structures of various solid phases. Despite the well-known short comings of the reference density-functional theory ab initio calculations, the fitted tight-binding model yields a semiquantitatively correct picture of the dynamics and a relatively good description of the microscopic structure, in fair accordance with the experimental data.

Microscopic structure and dynamics of molten Se50Te50 alloys

“…This indicates that the bond angles for Se atoms remain close to 100°and those of Te atoms close to 94°. This latter value is somewhat smaller than that the estimated experimental value in molten elemental Te ͑Ϸ100°, close to the value in the solid which is known to be preserved upon melting 29 ͒. As to the bond angle XSeŶ whose distribution peaks around 100°, is somewhat lower than the experimental and ab initio values 30 found in molten Se ͑Ϸ110°͒.…”

“…It seems that the accurate ab initio description of Se atoms somewhat compensates the deficiencies in the treatment of Te atoms ͑note that the stability of the cubic structure is overestimated 28 in the DFT for Te and this tends to favor bond angles close to 90°͒ as found in Ref. 29.…”

Density variations in liquid tellurium: Roles of rings, chains, and cavities

“…However, scattering experiments in Te have led to structure factors with considerable variation, 5,6 and it has been notoriously difficult to calculate structure factors and pair-correlation functions that resemble those measured. [7][8][9][10][11] This may be due in part to the relatively small samples considered in previous DF/MD simulations ͑64, 80, and 125 atoms per unit cell in Refs. 8, 9, and 11, respectively͒.…”

Pancharatnam-Berry phase and kinetic magnetoelectric effect in trigonal tellurium

“…The resulting 24-band tight-binding model is adequate to obtain the characteristics of the electronic band structure and effective masses around the Fermi energy. The spinorbit coupling of 0.45 eV which is not included in the original parametrization 36 is added later and the band gap is fitted to the experimental value of 0.335 eV. The inclusion of the spin-orbit interaction correctly splits the top two valence bands and accurately reproduces the famous "humps" around the valence band edge along the k z direction, Fig.…”