Heisenberg exchange enhancement by orbital relaxation in cuprate compounds

被引：73

作者：

vanOosten, AB ^{[1
]}

Broer, R ^{[1
]}

Nieuwpoort, WC ^{[1
]}

机构：

[1] UNIV GRONINGEN,CTR MAT SCI,NL-9747 AG GRONINGEN,NETHERLANDS

来源：

CHEMICAL PHYSICS LETTERS | 1996年 / 257卷 / 1-2期

关键词：

D O I：

10.1016/0009-2614(96)00498-8

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

We calculate the Heisenberg exchange J in the quasi-2D antiferromagnetic cuprates La2CuO4, YBa2Cu3O6, Nd2CuO4 and Sr2CuO2Cl2. We apply all-electron (MC)SCF and non-orthogonal CI calculations to [Cu2O11](18-), [Cu2O9](14-), [Cu2O7](10-) and [Cu2O7Cl4](14-) clusters in a model charge embedding. The (MC)SCF tripler and singlet ground states are well characterized by Cu2+ (d(x2-y2)) and O2-. The antiferromagnetic exchange is strongly enhanced by admiring relaxed (MC)SCF triplet and singlet excited states, in which a single electron is transferred from the central O ion to Cu. We ascribe this effect to orbital relaxation in the charge transfer component of the wavefunction. Close agreement with experiment is obtained.

引用

页码：207 / 212

页数：6

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