Lezaić M, Mavropoulos Ph, Enkovaara J, Bihlmayer G, Blügel S
Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Phys Rev Lett. 2006 Jul 14;97(2):026404. doi: 10.1103/PhysRevLett.97.026404. Epub 2006 Jul 13.
We propose two novel approaches to study the temperature dependence of the magnetization and the spin polarization at the Fermi level in magnetic compounds, and apply them to half-metallic ferromagnets. We reveal a new mechanism, where the hybridization of states forming the half-metallic gap depends on thermal spin fluctuations and the polarization can drop abruptly at temperatures much lower than the Curie point. We verify this for NiMnSb by ab initio calculations. The thermal properties are studied by mapping ab initio results to an extended Heisenberg model which includes longitudinal fluctuations and is solved by a Monte Carlo method.
我们提出了两种新颖的方法来研究磁性化合物中磁化强度和费米能级处自旋极化的温度依赖性，并将它们应用于半金属铁磁体。我们揭示了一种新机制，即形成半金属能隙的态的杂化取决于热自旋涨落，并且极化在远低于居里点的温度下会突然下降。我们通过从头算计算对NiMnSb验证了这一点。通过将从头算结果映射到一个扩展的海森堡模型来研究热性质，该模型包括纵向涨落，并通过蒙特卡罗方法求解。
