Pressure-induced phase transformation of In$_{2}$Se$_{3}$

Phase-change memory, with fast read-write speeds and small dimensions, will soon replace flash memory in our cell phones and tablets. This type of memory relies on phase change materials like indium selenide, In$_{2}$Se$_{3}$, a III-VI semiconductor that exists in multiple crystalline phases. To achieve controlled switching between phases, it is important to understand both the thermal and elastic properties of In$_{2}$Se$_{3}$. Using synchrotron x-ray diffraction and a diamond-anvil cell, a pressure-induced phase transition in powder In$_{2}$Se$_{3}$ from the $\alpha $ phase to $\beta $ phase was discovered at 0.7 GPa. This pressure is an order of magnitude lower than phase-transition pressures in most semiconductors. Raman spectroscopy experiments confirm this result. The bulk moduli are reported for both $\alpha $ and $\beta $ phases, and the $c/a$ ratio for the $\beta $ phase is shown to have a nonlinear dependence on pressure.