First-principles investigation on metal tantalum under conditions of electronic excitation

Abstract

Intense laser irradiated on metals can excite the electrons to high energy levels, and lead to a high electronic temperature established in a period of 10–100fs. The properties of metals would be affected by the high electronic temperature. In this paper, finite-temperature density functional theory with hot electron is used to investigate the free energy F and DFT energy E of metal tantalum varying with the supercell volume at different electronic temperatures. In addition, the formation enthalpies of a monovacancy are calculated at different electronic temperatures. The convergence tests for the k-points grid, the bands and the supercell size we selected are carefully carried out to improve accuracy of calculation. The calculated value of monovacancy formation enthalpy at ambient pressure and temperature is good agreement with previous experimental and theoretical values. What is more, the tendency of the monovacancy formation enthalpy increasing as the increment of the electronic temperature can explain the fact that the increase of the melting temperature under high electronic temperature.