Excitation-assisted disordering of GeTe and related solids with resonant bonding

GeTe and related phase-change alloys are characterized by resonant bonding, where the same p-orbitals are used to form bonds on both sides of the atom. In this work, we propose that inversion of the phase of the wave functions associated with electronic excitation plays a crucial role in structural phenomena, varying from ferroelectric-to-paraelectric phase transition to amorphization. A special case of coherent phase-flips may generate layer-by-layer evaporation and fabrication of graphene-like layer structures of phase-change materials if appropriate excitation conditions are satisfied for single crystal excitation.