Martensite transformation triggered with intense THz pulses

We demonstrate THz-induced martensitic transformation. We irradiated the intense THz pulses resonant for the lowest optical phonon on the surface of the partially stabilized zirconia plate and found that the clear evidence of martensitic transformation from tetragonal to monoclinic phase. We calculated the phonon dispersion in tetragonal zirconia and found the effective channel for the trigger of the transformation. Since the THz pulse excitation allows specific local shear deformation beyond thermal equilibrium, it will open new scheme of non-linear phononics in condensed matters.