Validity of the force theorem for magnetocrystalline anisotropy
Validity of the force theorem for magnetocrystalline anisotropy
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DOI：
10.1016/0304-8853(95)00936-1
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发表时间：
1996-07
影响因子：
2.7
通讯作者：
Xindong Wang;Ding-sheng Wang;R. Wu;A. Freeman
中科院分区：
文献类型：
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作者：
Xindong Wang;Ding-sheng Wang;R. Wu;A. Freeman
在局部密度理论的框架下，所谓力定理的有效性对于计算/理论确定磁晶各向异性（MCA）至关重要。该定理表明，自旋轨道耦合诱导的MCA能量是由两个磁化方向之间的完全相对论能带能量之差给出的，这两个磁化方向是用相同的自洽标量相对论势计算的。结果表明，自旋轨道耦合引起的电荷密度和自旋密度变化在自旋轨道耦合强度中为一阶消失。利用总能量泛函的平稳性，我们严格地建立了面/界面MCA力定理的有效性。我们证明了我们的论点也适用于MCA力定理的一个变体，并讨论了MCA力定理在立方晶体对称体系统中的应用问题。
The validity of the so-called force theorem is critical for the computational/theoretical determination of the magnetocrystalline anisotropy (MCA) in the framework of local density theory. This theorem states that the spin-orbit coupling induced MCA energy is given by the difference in the fully relativistic band energies between two magnetization directions calculated with the same self-consistent scalar-relativistic potential. We show that the charge- and spin-density variations caused by spin-orbit coupling vanish to first order in the spin-orbit coupling strength. By the stationary property of the total energy functional, we establish rigorously the validity of the force theorem for surface/interface MCA. We show that our arguments also apply to a variant of the MCA force theorem and discuss problems of applying the force theorem for MCA in bulk systems with cubic crystalline symmetry.