Pressure and temperature dependence of the structure of liquid InSb

Abstract

We investigate the structure of liquid InSb over a wide pressure range up to 20 GPa and a wide temperature range up to 1570 K by synchrotron x-ray diffraction. With increasing pressure along the melting curve, the local structure, which is anisotropic near the ambient pressure, becomes more isotropic. However, at pressures higher than about 10 GPa, the pressure-induced change becomes less prominent, and the local structure contracts almost uniformly. Structural parameters deviate significantly from those in simple liquid metals in this pressure region, revealing a stable liquid form with an anisotropic local structure. The analysis of $g(r)$ reveals that the liquid is possibly interpreted by the local structure of a single species, whose $g(r)$ is apparently expressed by a linear combination of $g(r)$ for $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{Sn}$-like and bcc-like local structures in a one-to-one ratio. This local structure is completely different from those present in its crystalline counterpart. Pressure and temperature dependence of the local structure is discussed in the relation to Rapoport two species model [J. Chem. Phys. 46, 2891 (1967)].