Polyamorphism in tin tetraiodide

Fuchizaki, Kazuhiro*; Sakagami, Takahiro*; Miyauchi, Arata*; Hamaya, Nozomu*; Hattori, Takanori   ; Katayama, Yoshinori

The results of the synchrotron X-ray diffraction on liquid SnI revealed the following characteristics on the phase transformation between low- and high-density liquids. (1) The local structure continuously changes with pressure. (2) The density shows no systematic change with pressure. The first one is confirmed by the continous pressure-induced change of off-tetragonalinity in the local structure. On the other hand, the second statement is still less convincible because it based on the indirect method to measure liquid density. To confirm the second statement, the direct measurement of the liquid density is necessary. For that purpose, we determined density from X-ray absorption of liquid sample. The results showed that the liquid density slightly jumps by the amount of 0.3 g/cc at 1.5 GPa, where the PT-melting curve shows a knick. Now we are trying to reveal the details based on more accurate data.