Structural transitions in liquidTe1−xSexalloys

Polarized and depolarized Raman scattering measurements are reported in liquid ${\mathrm{Te}}_{1-x}{\mathrm{Se}}_x$ alloys near the melting point. The results provide the first direct evidence for a structural transition within the range $x=0.2-0.3\mathrm{}$ from a twofold, chainlike bonding to a threefold, pyramidal As-like bonding. Higher-temperature polarized Raman measurements at $x=0.3\mathrm{}$ do not indicate a twofold to threefold transition, as has been suggested, but rather indicate increased intrachain disorder.