Spin polarization on Fermi surfaces of metals by the KKR method
Spin polarization on Fermi surfaces of metals by the KKR method
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通过 KKR 方法测量金属费米表面的自旋极化
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
I. Mertig
中科院分区：
文献类型：
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作者：
M. Gradhand;M. Czerner;D. Fedorov;P. Zahn;B. Yavorsky;L. Szunyogh;I. Mertig
采用相对论性的Korringa-Kohn-Rostoker绿色函数和能带结构方法，分析了磁性金属和非磁性金属费米面上电子态的自旋期望值。结果表明，对于相对较轻的元素，如铜的自旋态是很好地定义。甚至在相当重的单价元素如Au的情况下，也可以将所有电子状态分离为“上”和“下”自旋极化状态。相比之下，对于重多价金属如Pt，自旋算符的期望值在费米面的大区域中可以接近于零。在这种情况下，明确定义的“向上自旋”和“向下自旋”状态的非相对论语言不再有效。对于磁性材料，相对论费米面相对于非相对论多数和少数片改变了它们的拓扑结构，因为自旋轨道驱动避免了带的交叉。结果，出现自旋极化消失的区域。
With the implementation of a relativistic Korringa-Kohn-Rostoker Green's function and band-structure method, we analyze the spin-expectation value of the electron states on the Fermi surface of nonmagnetic as well as magnetic metals. It is shown that for relatively light elements such as Cu the spin states are well defined. A separation of all electron states to ``up'' and ``down'' spin-polarized states can be done even in the case of quite heavy but monovalent elements such as Au. In contrast, for heavy polyvalent metals such as Pt, the expectation value of the spin operator can be close to zero in large regions of the Fermi surface. In this case the nonrelativistic language of well-defined ``spin-up'' and ``spin-down'' states is not valid anymore. For magnetic materials, the relativistic Fermi surfaces change their topology with respect to the nonrelativistic majority and minority sheets because of spin-orbit driven avoided crossings of the bands. As a result, regions with vanishing spin polarization appear.