Pressure dependence of the structure of liquid InAs up to 13 GPa

The structure of liquid InAs has been investigated at pressures up to 13 GPa by means of synchrotron x-ray diffraction. The results show a change of the contraction behaviour. Below 9 GPa, liquid InAs contracts almost uniformly, which is inferred from there being no remarkable pressure-induced change in the shapes of the structure factor, S(Q), and the pair distribution function, g(r), and in the coordination number. Above 9 GPa, the liquid contracts nonuniformly, which is inferred from the gradual change in the shapes of S(Q) and g(r) and the continuous increase of the coordination number from 6 to 7. The analysis of g(r) shows that liquid InAs consists of β-Sn-like and bcc-like local structures, which do not appear in crystalline InAs, throughout the whole pressure region up to 13 GPa. The fraction of the high-pressure form (bcc-like local structure) increases above 9 GPa, while it is almost constant below 9 GPa. These findings suggest that liquid InAs transforms from the state consisting of a relatively stable local structure into a transient state in which the local structure continuously changes with pressure