Temperature effect of the pressure coefficients for multi-phonon coupling in B3-ZnS

Abstract

The zincblende (B3) to rock salt (B1) in ZnS is a typical pressure-induced phase transition. Meanwhile, B3-ZnS exhibits distinctive multi-phonon coupling behavior. Despite previous studies have explored the B3–B1 transition and phonon behavior in ZnS at room temperature, the effects of low temperature have yet to be experimentally verified. This has resulted in the absence of experimental data on the pressure–temperature (P–T) phase diagram at low temperatures. Here, we probe the pressure-induced B3–B1 phase transition and phonon evolution behavior of ZnS at low temperatures (90–300 K) using isothermal compression Raman spectroscopy. We experimentally determine the ZnS B3–B1 phase boundaries at low temperatures and obtain the corresponding Clapeyron slope, dP/dT = −16.4 ± 2.1 MPa/K. In addition, we found that the pressure coefficients (KiT) of all phonon modes of B3-ZnS decrease with decreasing temperature. This is mainly due to the reduction of anharmonic effects at low temperatures. Further, KiT of the multi-phonon coupling states are always larger than those of the single phonon state.