Ab initio determination of an extended Heisenberg Hamiltonian in CuO2 layers
Accurate ab initio calculations on embedded Cu4O12 square clusters, fragments of the La2CuO4 lattice, confirm a value of the nearest neighbor antiferromagnetic coupling (J = 124 meV) previously obtained from ab initio calculations on bicentric clusters and in good agreement with experiment. These ca...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2001 |
| País: | España |
| Institución: | Universidad de Sevilla (US) |
| Repositorio: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:idus.us.es:11441/147748 |
| Acceso en línea: | https://hdl.handle.net/11441/147748 https://doi.org/10.1007/s100510170181 |
| Access Level: | acceso abierto |
| Palabra clave: | 74.25.Ha electronic structure 74.25.Jb magnetic properties 75.30.Et exchange and superexchange interactions |
| Sumario: | Accurate ab initio calculations on embedded Cu4O12 square clusters, fragments of the La2CuO4 lattice, confirm a value of the nearest neighbor antiferromagnetic coupling (J = 124 meV) previously obtained from ab initio calculations on bicentric clusters and in good agreement with experiment. These calculations predict non negligible antiferromagnetic second-neighbor interaction (J′ = 6.5 meV) and four-spin cyclic exchange (K = 14 meV), which may affect the thermodynamic and spectroscopic properties of these materials. The dependence of the magnetic coupling on local lattice distortions has also been investigated. Among them the best candidate to induce a spin-phonon effect seems to be the movement of the Cu atoms, changing the Cu-Cu distance, for which the variation of the nearest neighbor magnetic coupling with the Cu-O distance is ΔJ/ΔdCu-O ∼ 1700 cm-1 Å-1. |
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