Ultrafast laser-induced phase transitions in amorphous GeSb films

Phys Rev Lett. 2001 Apr 16;86(16):3650-3. doi: 10.1103/PhysRevLett.86.3650.


Time-resolved measurements of the spectral dielectric function reveal new information about ultrafast phase transitions induced by femtosecond laser pulses in Sb-rich amorphous GeSb films. The excitation generates a nonthermal phase within 200 fs. The dielectric function of this phase differs from that of the crystalline phase, contrary to previous suggestions of a disorder-to-order transition. The observed dielectric function is close to that of the liquid phase, indicating an ultrafast transition from the amorphous phase to a different disordered state.