Green's function theory for spin- 1 2 ferromagnets with an easy-plane exchange anisotropy

Daisuke Yamamoto*, Synge Todo, Susumu Kurihara

*この研究の対応する著者

研究成果: Article査読

8 被引用数 (Scopus)

抄録

The many-body Green's function theory with the random-phase approximation is applied to the study of easy-plane spin-1/2 ferromagnets in an in-plane magnetic field. We demonstrate that the usual procedure, in which only the three Green's functions Siμ; Sj- (μ=+,-,z) are used, yields unreasonable results in this case. Then the problem is discussed in more detail by considering all combinations of Green's functions. We can derive one more equation, which cannot be obtained by using only the set of the above three Green's functions, and point out that the two equations contradict each other if one demands that the identities of the spin operators are exactly satisfied. We discuss the cause of the contradiction and attempt to improve the method in a self-consistent way. In our procedure, the effect of the anisotropy can be appropriately taken into account and the results are in good agreement with the quantum Monte Carlo calculations.

本文言語English
論文番号024440
ジャーナルPhysical Review B - Condensed Matter and Materials Physics
78
2
DOI
出版ステータスPublished - 2008 7月 30

ASJC Scopus subject areas

  • 凝縮系物理学

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