METALLIC FERROMAGNETISM IN A SINGLE-BAND MODEL .4. EFFECT OF PAIR HOPPING
METALLIC FERROMAGNETISM IN A SINGLE-BAND MODEL .4. EFFECT OF PAIR HOPPING
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DOI：
10.1103/physrevb.43.705
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发表时间：
1991-01-01
影响因子：
3.7
通讯作者：
HIRSCH, JE
中科院分区：
文献类型：
--
作者：
HIRSCH, JE
最近提出最近邻Wannier轨道J中电子间的库仑交换矩阵元在金属铁磁性中起着重要作用。 除了在最近邻位点上交换电子之外，它还对汉密尔顿量产生了对跳跃的贡献。 在这里，我们研究的效果对跳跃项的铁磁性的趋势。 它强调的重要作用，这些相互作用在铁磁性的结果从它们的动量依赖性在固态环境中发挥。我们发现，对跳跃项进一步增强了铁磁性的倾向，并扩大了不饱和铁磁性发生的参数范围。 当在位排斥力U较大时，它的影响变小。 交换和对跳跃的结合产生了键电荷排斥，金属铁磁性可以理解为电子避免这种直接库仑相互作用的趋势。
The Coulomb-exchange matrix element between electrons in nearest-neighbor Wannier orbitals J has recently been proposed to play a fundamental role in metallic ferromagnetism. In addition to exchanging electrons on nearest-neighbor sites, it gives rise to a pair-hopping contribution to the Hamiltonian. Here we examine the effect of the pair-hopping term on the tendency to ferromagnetism. It is stressed that the important role that these interactions play in ferromagnetism results from their momentum dependence in the solid-state environment. We find that the tendency to ferromagnetism is further enhanced by the pair-hopping term, and the parameter range where unsaturated ferromagnetism occurs is enlarged. Its effect becomes small for large on-site repulsion U. The combination of exchange and pair hopping gives rise to bond-charge repulsion, and metallic ferromagnetism can be understood as arising from the tendency of electrons to avoid this direct Coulomb interaction.