Non-perturbation electron-vibration interaction simulations of quantum effects in phase transitions under high pressure

A long-standing challenge in high-pressure physics and chemistry is determining locations of phase transitions in the pressure-volume-temperature space and simultaneously characterizing them. Accurate non-perturbation electron-vibration interaction simulations recently developed applied to computationally studies of phase transitions under high pressure. Simulations show that some quantum effects in phase transitions play an important role at high pressure. These quantum effects include the quantum degeneracy in energy band structures and electron-vibration interactions. Under mechanical compression, electron-vibration interactions can strongly couple the quantum degeneracy to stretch chemical bonds through a specific reaction vibrational mode and thus induce a phase transition. The vibrational amplitude of the reaction mode can apply to estimate transformation temperature in good agreement with experiments. Therefore, non-perturbation electron-vibration interaction simulations can identify phase transition locations in the pressure-volume-temperature space. More importantly, such simulations provide numerical modelling access to the physics and chemistry of quantum materials under high pressure.