Suppressing Electron-Phonon Coupling through Laser-Induced Phase Transition.

Using first-principle calculations, we introduced a strategy of laser-induced phase transition that suppress electron-phonon couplings in crystal lattice. We explained unusual irreversible phase transitions in previous experiments on MoTe2 and NaYF4 crystals. Laser irradiations produced local heats in 2H-MoTe2 and Hex NaYF4, driving atom reorganizations toward new lattices. The reorganization with effective electron-phonon couplings continues with spontaneously generated heats, whereas a 1T'-MoTe2 and a metastable cubic NaYF4 phases were kept because of suppressed vibrational relaxations. Long time laser treatments create phases with weak electron-phonon couplings. Such irreversible transitions guarantee complete conversions, opening a new door to selective material modifications.