Pressure- and temperature-induced M 3 phonon softening in ReO 3

摘要: We have investigated the temperature and pressure variation of ${M}_{3}$ phonon mode ${\text{ReO}}_{3}$ by inelastic neutron scattering on a single crystal. The energy decreases with decreasing contrary to normal hardening behavior. this also increasing tends zero at about 3.5 kbar $T=150\text{ }\text{K}$. softening drives pressure-induced phase transition in ${\text{ReO}}_{3}$. temperature-induced lowering can be understood from known negative thermal-expansion behavior fact that high-pressure approached ambient cooling. In order understand we done lattice-dynamical calculations support qualitative arguments given above.