Session P20 - Structural Phase Transitions.
MIXED session, Wednesday afternoon, March 22
208A, MCC
Heat-induced structural phase transitions of noble metals silver and gold are studied using 1.5 eV, 120 fs ultrashort laser pulses. The dynamics of heating process is monitored by measuring the time evolution of the dielectric constants following optical excitation, which shows behavior consistent with that reported previously. Fluence-dependent dielectric constants in silver and gold show similarities with the photon-energy-dependent dielectric constants, which in fact indirectly map out the degree of the heat-induced electronic disorder in noble metals. The results demonstrate, for the first time, that the heat-induced structural phase transition in metal is in fact tied to the electronic disorder and band structure collapse.