Remark on the glass-forming ability in GexSe1−x and AsxSe1−x systems

Some experimental results from new and old literature are summarized indicating that a maximum of glass-forming ability in GexSe1−x (I) and AsxSe1−x (II) systems lies close to an eutectic point; it is at x≅0.09 (I), and x≅0.20 (II). This one is more Se-rich than the Phillips–Thorpe threshold where the mean coordination number 〈CN〉 equals 2.4 (x=0.2 (I), and x=0.4 (II), respectively). It is speculated that the origin of the maximum of the glass-forming ability in GexSe1−x and AsxSe1−x systems could in fact result from `specificʹ bonding arrangement, that is an optimal cross-linking of the short Se-chains crossed together by Ge or As atoms.