Competing stoichiometric phases and the intermediate phase in GexSe1-x glasses

Raman and calorimetric studies on GexSe1-x glasses have provided evidence for the existence of the intermediate phase (LP) in chalcogenide and other glasses. Ab initio molecular dynamics models of these glasses are discussed, and an atomistic picture of the IP, based upon the models and available experiments, is presented. Analysis of our models reveals that the IP in GexSe1-x glasses may arise from the competition between amorphous GeSe2 and a polymeric a-Se phase, which gives rise to the non-monotonic evolution of the network parameters through the IP window. A possible electronic signature of the IP in terms of the shift in the conduction edge in the IP range is also observed. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim