Modulation of Structural Symmetry-Breaking and Thermal Properties by Valence Electron Structures of UV (U = Ta, Nb; V = As, P) Weyl Semimetals

Weyl semimetals have received considerable attention due to their special energy-band characteristics for potential applications as topological quantum devices. In this study, an empirical electronic theory of solids and molecules, which is built in real space, is used to study the valence electron structures, spatial inversion symmetry-breaking, and melting points of UV (U = Ta, Nb; V = As, P) Weyl semimetals for revealing the nature of their topological characteristics. The theoretical bond lengths and cohesive energies as well as melting points of UV are consistent with their experimental ones. The distribution of hybrid-energy levels of spatial inversion symmetry-breaking is strongly related to the number of valence electrons, which is similar to that of first principles. The cohesive energy and melting point show a positive correlation with the number of covalence electrons and the number of covalence electron pairs on the strongest bond. It is suggested that the topological property of the energy-band structure is also revealed by the valence electron structure in real space. The study indicates that the simple EET model provides a distinct insight into the topological property of the energy-band structure.