Transport properties of liquid metals and semiconductors from molecular dynamics simulation with the Kubo-Greenwood formula
Short but intense laser pulses may produce the high surface temperatures of metal or semiconductor targets exceeding the corresponding melting points. Hydrodynamic modeling of nano-scale fragmentation of a thin surface layer is feasible if the reflectivity and heat conductivity coefficients, usually obtained from experiments, are available. However, for such materials as silicon and titanium the experimental electric resistivity and heat conductivity are available only in narrow temperature ranges above the melting points. On the other hand, the heated surface layer keeps its initial density during a short two-temperature stage because the timescales of both femtosecond laser heating and electron-ion energy exchange are too short for material expansion. The short-lived high-temperature states of materials in this layer are also challenging for experimental study with techniques such as electrical explosion of wires or films.We perform accurate simulations of several materials in such states, including aluminum, copper, gold, silicon, and titanium, at the corresponding equilibrium volumes at room temperature and along their liquid-vapor coexistence curves using both classical and quantum molecular dynamics. The corresponding electron transport properties calculated by the Kubo-Greenwood theory are presented.