高压下CaSiO_3钙钛矿的从头算研究(英文)

Ab initio study of CaSiO_3 perovskite at high pressure

利用考虑声子效应的准谐近似Debye模型势结合基于密度泛函理论的平面波赝势方法,研究了高温高压下CaSiO_3钙钛矿的热力学性质.在常温常压下CaSiO_3钙钛矿的状态方程与实验结果吻合得很好.获得了压强上升到150 GPa,温度上升到2000 K时CaSiO_3钙钛矿的热力学参量体积模量、热膨胀和热容与温度和压强的关系.

The thermodynamic properties of CaSiO3 perovskite were predicted at high pressures and temperatures using the Debye model for the first time. This model was combined with the plane wave pseudopotential method within the local density approximation in the framework of density functional theory, and it took into account the phononic effects within the quasi-harmonic approximation. It was found that the calculated equation of state is in excellent agreement with the observed values at ambient condition. Based on the first-principles study and the Debye model, the thermal properties including the bulk modulus, the heat capacity and the thermal expansion were obtained in the whole pressure range from 0 to 150 GPa and temperature range from 0 to 2 000 K.