Electron-phonon driven superconductivity in the novel A15 phase of the Ti–Te system under pressure

Abstract

We investigate the high-pressure phase diagram of Ti–Te system using first-principles calculations combined with evolutionary crystal structure prediction. Given the isostructural behavior of Se and Te at higher pressures, the same stoichiometric ratios as in the Ti–Se system were found in the Ti–Te system at high pressures. A novel A15 stable phase Ti3Te is predicted under pressure. Following this, its electronic, mechanical, vibrational, dynamical and superconducting properties at 0 GPa have been systematically scrutinized. The Ti-d orbitals occupy mainly at the Fermi level and Ti3Te exhibits intrinsic metallic property. Meanwhile, the electron-phonon coupling constant λ is 1.03, and the calculated superconducting transition temperature Tc (μ∗ = 0.10–0.15) is 14.2-11 K. Furthermore, we have studied the A15 structural candidates that can be formed by Ti and sulphur group elements under pressure. The mechanism of pressure-enhanced superconductivity present in these structures is also elucidated from a microscopic perspective.