Phase transition in ZnSe at high pressures and high temperatures

The phase transition boundary between the zinc blende and the rock-salt structure in zinc selenide (ZnSe) was determined using high-pressure experiments combined with the synchrotron X-ray diffraction technique. Significant hysteresis in the phase transition was not observed at high temperatures. The transition pressure was extrapolated to be 13.3 GPa at 300 K, and the dP/dT slope of the phase boundary had a negative dependence of −0.0033 GPa/T. As this transition pressure was used as the pressure standard in the high-pressure experiments, the new value influences a wide range of high-pressure science. This negative dependence is similar to those of semiconductor–metal transitions, such as ZnS, GaAs, and GaP. We found a linear relationship between the semiconductor–metal transition pressures and dP/dT slopes in II–VI and III–V compounds.