Structural phase transition in crystalline HgSe: Low-temperature and high-pressure Raman spectroscopic investigation
https://doi.org/10.1016/j.jpcs.2025.112977
At ambient pressure and temperature, Raman spectroscopy showed A1, E and T2 modes in HgSe which suggested coexistence of zinc blende (zb) and cinnabar (cin) phase. A blue shift of A1 and E Raman modes was observed with increasing temperature, which was explained by the reduction of lattice constant. Experimental results of Raman spectroscopy were consistent with the DFT calculation, both predicted transition to cin phase at moderate pressure of 1.5–1.8 GPa, and a complete absence of the Raman modes was observed above pressure of 16 GPa, confirming the transformation to the NaCl structure. The pressure-dependent frequency shift, linewidth and Raman intensity was explained by eigenvectors of vibrational symmetry of the modes, anharmonic effect and changes in polarizability.