Piezoelectric (Stress) Coefficients Of Barium Titanate By Molecular Dynamics Simulations

Barium titanate(BaTiO3), which is the first discovered perovskite type of ferroelectric material, has always been the research focus in the solid physics. It has excellent piezoelectric properties, reversible high strain properties caused by electronic field as well as wonderful nonlinear optical properties. Therefore, it has broad prospects for application in piezoelectric, high strain and nonlinear optics fields.With the emergence and development of the electromechanical systems of nano-scale, the mechanical behavior research of nano-scale piezoelectric materials is becoming more and more important. However, because the size of materials keeps reducing, continuous medium theory has become unable to explain the new mechanical phenomena at nano scale. Therefore, systematic mechanical behavior should be studied through the basic atomic and molecular movements. The MD simulation has tremendous development and application prospects for its simple program, small computation and higher capacity to calculate the number of atoms than first-principle calculation and other nano-scale method.This paper summarizes the basic principles of MD, control method and related details. The program of MD is designed with Fortran. MD simulations of a single crystal barium titanate (BaTiO3) have beed performed at 300k under various applied external electric fields. Barium titanate is described by using a suitable pair potential function. The influences of the external field and temperature on the piezoelectric (stress) coefficients of barium titanate are carefully investigated. It is shown that the stress vary with increasing strength of electric field. The piezoelectric (stress) coefficients are calculated in terms of MD, And we compare the results with experimental data. The results show that the temperature has an obvious influence on the piezoelectric (stress) coefficient e33 also.