Optically-controlled phonon-specific phase transitions from graphite to diamond
摘要
Controlling phase transition processes and the atomic structure of new states with light has emerged as a highly challenging frontiers in condensed matter physics and materials science. The conversion of graphite to diamond typically relies on high-pressure and high-temperature conditions, while the advent of ultrafast laser has opened entirely new possibilities for dynamically controlling such structural transformation under non-thermodynamic state. Herein, employing state-of-the-art first-principles non-adiabatic molecular dynamics simulations, we elucidate ultrafast pathways of light-induced graphite-to-diamond phase transition and reveal the laws governing the selective formation of cubic or hexagonal diamond, as well as their subsequent structural evolution, by regulating laser parameters. Such optically controlled diamond formation stems from early-stage structural reconstruction driven by electron-phonon couplings and indirect excitation of specific phonon modes (e.g.