Car-Parrinello molecular dynamics in a finite homogeneous electric field
Car-Parrinello molecular dynamics in a finite homogeneous electric field
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有限均匀电场中的 Car-Parrinello 分子动力学
DOI：
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发表时间：
2003
期刊：
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通讯作者：
Alfredo Pasquarello
中科院分区：
文献类型：
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作者：
P. Umari;Alfredo Pasquarello
我们引入了一个变分总能量泛函来处理具有周期边界条件的有限均匀电场，并表明该泛函可以在Car Parrinello分子动力学方案中实现。与电场的耦合是通过极化的Berry相位表达式实现的。这个扩展的功能的最小化给出了一个基态，它描述了在电场中的极化状态。对于一个晶体系统，基态的扩展功能保持布洛赫对称性。该方法的可靠性证明了在体MgO的情况下的玻恩有效电荷，和高-和低-频率的介电常数。在后一种情况下，我们通过在有限电场的存在下进行阻尼分子动力学来评估静态介电常数，完全避免了动力学矩阵的计算。
We introduce a variational total‐energy functional to treat finite homogeneous electric fields with periodic boundary conditions and show that this functional can be implemented within a Car‐Parrinello molecular dynamics scheme. The coupling to an electric field is achieved through the Berry‐phase expression of the polarization. The minimization of this extended functional gives a ground state which describes the polarized state in an electric field. For a crystalline system, the ground state of this extended functional preserves the Bloch symmetry. The reliability of the method is demonstrated in the case of bulk MgO for the Born effective charges, and the high‐ and low‐frequency dielectric constants. In the latter case, we evaluated the static dielectric constant by performing a damped molecular dynamics in the presence of a finite electric field, completely avoiding the calculation of the dynamical matrix.