Pressure-induced structural change of liquidCdTeup to23.5GPa

Abstract

The structure of liquid $\mathrm{CdTe}$ was investigated at pressures up to $23.5\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ using synchrotron x-ray diffraction. The structure factor, $S(Q)$, and the pair distribution function, $g(r)$, drastically change in two pressure regions, 1.8--3.0 and $7.0--9.0\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$, accompanied with marked increase in the average coordination number. These findings suggest that there exists at least three stable liquid forms below $23.5\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. The pressure interval of the structural change is much smaller compared to other liquids of tetrahedrally bonded materials. Comparing the shapes of $S(Q)$ and $g(r)$ and other structural parameters with the respective data for the reference materials reveals that the lowest- and intermediate-pressure forms have the same local structures as the crystalline counterpart (zinc-blende-like local structure and a $\mathrm{NaCl}$-like local structure), while the highest-pressure form has a different local structure from that in the crystalline form.