Pressure-induced B1-to-B2 phase transition in AgSbSe$_2$*

We have investigated the pressure-induced B1-to-B2 phase transitions in AgSbSe$_{2}$. High pressure x-ray diffraction experiments clearly show that the process starts at 20 GPa and completes at 55 GPa. Our density-functional calculations are in good agreement with the experiment and confirm the B1 to B2 transition which is similar to AgSbTe$_{2}$. The possible intermediate structure for B1-to-B2 transition in AgSbSe$_{2}$ occurring at 21-54 GPa is under investigation. Its similarity and difference to AgSbTe$_{2}$ will be discussed in this study.