Surface physical changes which were due to fs pulsed laser irradiation were observed in a new regime of extremely low laser fluence (less than 0.1% of the single-shot damage fluence) and large number of shots (above 1010). No bulk damage was detected. The surface disorder was reversed by thermal annealing at 580C. A new mechanism was proposed for fs laser-induced surface physical reactions. Disorder was caused by a surface dangling-bond hole-induced lattice instability which depressed the barrier, to disorder, to the order of kT. This occurred during high-density local fluctuations; even though the mean hole density was far lower than that needed for global instability.

Femtosecond Laser-Induced Disorder of the (1 x 1)-Relaxed GaAs(110) Surface H.Kwak, K.C.Chou, J.Guo, H.W.K.Tom: Physical Review Letters, 1999, 83[18], 3745-8