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

Some experimental results from new and old literature are summarized indica ting 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 congruent to 0.09 ( I), and x congruent to 0.20 (II). This one is more Se-rich than the Phillip s-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 system s could in fact result from 'specific' bonding arrangement, that is an opti mal cross-linking of the short Se-chains crossed together by Ge or As atoms . (C) 2000 Elsevier Science B.V. All rights reserved.