| Rigidity transitions in binary Ge±Se glasses and the intermediate phase (2008) | |||||||||||||
Abstract | |||||||||||||
| Raman scattering measurements, undertaken on bulk GexSe1 x glasses at 0 < x < 1=3, show evidence of two rigidity transitions as monitored by compositional trends in corner-sharing �mCS) and edge-sharing …mES † Ge…Se1=2 † 4 mode frequencies. A second-order transition from a ¯oppy to an unstressed rigid phase occurs near xc…1 † ˆ0:20…1 † where both mCS…x † and mES…x † show a kink. A ®rst-order transition from an unstressed rigid to a stressed rigid phase occurs near xc…2 † ˆ0:26…1†, where m2 CS…x † displays a step-like discontinuity between x ˆ 0:25 and 0.26 and a power-law behavior at x> xc �2). In sharp contrast, earlier micro-Raman measurements that use at least three orders of magnitude larger photon ¯ux to excite the scattering, showed only one rigidity transition near xc ˆ 0:23, the mid-point of the intermediate phase �xc…1 † < x < xc…2†). Taken together, these results suggest that the intermediate phase, observed in the low-intensity Raman measurements, undergoes a light-induced melting to a random network in the micro-Raman measurements. | |||||||||||||
Publication details | |||||||||||||
| |||||||||||||