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Modèles de dimères classiques et quantiques pour des systèmes d'électrons corrélés bidimensionnels
| Content Provider | Semantic Scholar |
|---|---|
| Author | Trousselet, Fabien |
| Copyright Year | 2009 |
| Abstract | This thesis treats various topics about strongly correlated electronic systems in 2 spatial dimensions (compounds with geometrical frustration, resonating valence bond phases) described in terms of dimer models. A part of this thesis discusses classical dimer models, and especially an interacting dimer model on an anisotropic triangular lattice, presenting critical phases descriptible with help of conformal field theories; based on these theories, the numerical analysis of this model allowed to characterize the conditions for the existence of criticality, and more generally the phase diagram in function of interaction parameters and of the lattice anisotropy. Another part treats a system of electrons on a two-dimensional version (checkerboard lattice) of the pyrochlore lattice, at commensurable particle filling. In a strong interacting limit, local constraints on charge repartition are those of dimers on the square lattice, thus an effective quantum dimer model is derivated. This model differs from the Rokhsar-Kivelson model (motivated by resonating valence bond phases in cuprates) by, here, an additional spin degree of freedom for each dimer. A study with exact diagonalisation, completed by a variational approach and arguments from from perturbation theory, allowed to identify an insulating crystal phase of resonating singlets; an extension of this model to small but finite electron mobility was eventually consitered with the aim to characterize the transition from this insulator to a metallic state when increasing the ration of the electron mobility over interaction strength. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://tel.archives-ouvertes.fr/tel-00404146/document |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
