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pro vyhledávání: '"Gellé, Alain"'
Autor:
Gellé, Alain
Ce travail comporte deux partie, l'une de développement méthodologique, l'autre concerne l'étude ab-initio, par une méthode de spectroscopie de fragments immergés dans un bain, des composés Sr(14-x)Ca(x)Cu(24)O(41).Le travail méthodologique pr
Externí odkaz:
http://tel.archives-ouvertes.fr/tel-00124312
http://tel.archives-ouvertes.fr/docs/00/12/43/12/PDF/these.pdf
http://tel.archives-ouvertes.fr/docs/00/12/43/12/PDF/these.pdf
Publikováno v:
Europhysics Letters (EPL) 88, 3 (2009) 37003
We propose a new ab initio method designed for the accurate calculation of effective exchange integrals between atoms with numerous open-shells. This method applies to ferromagnetic as well as antiferromagnetic exchange, direct or ligand-mediated exc
Externí odkaz:
http://arxiv.org/abs/0904.4231
Publikováno v:
J. Chem. Phys. 128 (2008) 244716
An efficient real space method is derived for the evaluation of the Madelung's potential of ionic crystals. The proposed method is an extension of the Evjen's method. It takes advantage of a general analysis for the potential convergence in real spac
Externí odkaz:
http://arxiv.org/abs/0804.2747
An efficient real space method is derived for the evaluation of the Madelung's potential of ionic crystals. The proposed method is an extension of the Evjen's method. It takes advantage of a general analysis for the potential convergence in real spac
Externí odkaz:
http://arxiv.org/abs/0711.2888
We study the competition between antiferromagnetic order and valence bond solid formation in a two-dimensional frustrated spin-1/2 model. The J1-J2 model on the square lattice is further frustrated by introducing products of three-spin projectors whi
Externí odkaz:
http://arxiv.org/abs/0704.2352
Publikováno v:
physica B 359-361 (30/04/2005) 1258
The present paper studies, using ab-initio calculations, the influence of the incommensurate structural modulations on the low energy physics of the $Sr\_{14-x}Ca\_xCu\_{24}O\_{41}$ oxides. On-site, nearest-neighbor and next-nearest-neighbor effectiv
Externí odkaz:
http://arxiv.org/abs/cond-mat/0502105
Publikováno v:
physical review B 74 (22/12/2006) 235115
We studied the effects of the incommensurate structural modulations on the ladder subsystem of the $Sr\_{14-x}Ca\_{x}Cu\_{24}O\_{41}$ family of compounds using ab-initio explicitly-correlated calculations. From these calculations we derived $t-J$ mod
Externí odkaz:
http://arxiv.org/abs/cond-mat/0411135
Publikováno v:
european physical Journal B 43 (11/02/2005) 29
We extracted, from strongly-correlated ab-initio calculations, a complete model for the chain subsystem of the $Sr_{0.4}Ca_{13.6}Cu_{24}O_{41}$ incommensurate compound. A second neighbor $t-J+V$ model has been determined as a function of the fourth c
Externí odkaz:
http://arxiv.org/abs/cond-mat/0410204
Publikováno v:
european physical Journal B 46 (07/09/2005) 489
A second neighbor $t-J+V$ model for the chain subsystem of the $Sr\_{14}Cu\_{24}O\_{41}$ has been extracted from ab-initio calculations. This model does not use periodic approximation but describes the entire chain through the use of the four-dimensi
Externí odkaz:
http://arxiv.org/abs/cond-mat/0410203
Publikováno v:
J. Chem. Phys. 118, 3966 (2003)
The present work analyzes the importance of the different components of the environment effects on the local spectroscopy of extended strongly correlated systems. It has been found that the usual formal charge definition of the charge transfer and Ma
Externí odkaz:
http://arxiv.org/abs/cond-mat/0312377