Magnetically driven phase transitions with a large volume collapse in MnSe under pressure: A DFT+DMFT study

We present a theoretical study of spectral, magnetic, and structural properties of the manganese selenide under pressure within the DFT+DMFT method combining density functional theory with dynamical mean-field theory. Our results reveal that a high-spin to low-spin transition occurs upon compression at volumes below 33 ${\AA{}}^{3}$. The spin-state transition is accompanied by a metal-insulator transition and a structural phase transition with the large volume collapse of $\ensuremath{\sim}20%$ from the cubic B1 structure to the high-pressure MnP-type B31 structure at about 27 ${\AA{}}^{3}$. We find that the spin-state transition is the main driving force for the structural transition.