Polarization dependent optical control of atomic arrangement in multilayer Ge-Sb-Te phase change materials

We report the optical perturbation of atomic arrangement in the layered in GeTe/Sb2Te3 phase change memory material. To observe the structural change, the coherent A(1) mode of GeTe4 local structure was investigated at various polarization angles of femtosecond pump pulses with the fluence at <= 78 mu J/cm(2). p-polarization found to be more effective in inducing the A(1) frequency shift that can be either reversible or irreversible depending on the pump fluence. The predominant origin of this shift is attributed to rearrangement of Ge atoms driven by anisotropic dissociation of the Ge-Te bonds along the [111] axis after the p-polarized pulse irradiation. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768785]