Smeared first-order phase transition in chalcogenide melts

It is shown that the semiconductor-metal transition (SMT) in chalcogenide g lass-forming liquids takes place over a range of temperatures and is accomp anied by an endothermic effect and structural transformation. Therefore, it should be referred to as a smeared first-order phase transition with the m icro-regions of co-operative structural transformations involving 10(2) or more atoms. Apparently, this mechanism of the SMT is determined by the stru cture of glass-forming liquids and glasses in which there are structurally self-consistent regions, i.e., by medium-range order. (C) 1999 Elsevier Sci ence B.V. All rights reserved.