Ab initio calculation of elastic constants of SiO_2 stishovite and #alpha#-quartz

摘要

We present theoretical ab initio results for the elastic constants of two different phases of SiO_2, stishovite and #alpha#-quartz using the plane-wave-pseudopotential method. Our calculated values are in very good agreement with the experimental data as well as some of the existing model calculations. SiO_2 is one of the most abundant minerals in the earth's mantle. Therefore, the knowledge of its elastic behavior will be very important from a seismology point of view. Our calculated sound velocities are presented and are accordingly also in good agreement with those derived from experiment.