Nuclear quadrupole resonance in the glassy Cu-As-S and Cu-As-Se systems

Abstract

Nuclear quadrupole resonance (NQR) of $^{75}\mathrm{As}$ has been used to study bonding arrangements in the metal chalcogenide glass systems, Cu-As-S and Cu-As-Se. In the compositions ${\mathrm{Cu}}_{\mathrm{x}}$(${\mathrm{As}}_{2/5}$${\mathrm{Z}}_{3/5}$${)}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$, where Z=S or Se, the $^{75}\mathrm{As}$ NQR spin-echo measurements are consistent with the appearance of As-As bonds whose density increases with x. For the compositions (Cu-As-Se) the NQR measurements yield no evidence for the presence of As-As bonds. Both of these results are consistent with a recent structural model proposed to explain the local structural order in metal chalcogenide glasses.