Mechanisms of structural changes induced by electronic excitations in solids

Abstract

An overview is presented on various structural changes in non-metallic materials induced by electronic excitations from the viewpoints of energy transfer, relaxation, and symmetry breaking. Photonic irradiation to solids excites valence and/or core electrons, which creates imbalance in atomic forces. The key mechanism of extrinsic self-trapping is introduced to understand strong carrier localization and symmetry-breaking structural instability in connection with the Jahn-Teller effect. Structural changes induced by intense photonic irradiation are discussed including desorption, phase transition, laser annealing, and nonthermal melting.