Mass-imbalanced Hubbard model on a 2D square lattice

Kaffashnia, Amir (2019) Mass-imbalanced Hubbard model on a 2D square lattice. Masters thesis, Memorial University of Newfoundland.

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The Hubbard model (HM) and the Falicov-Kimball model (FKM), which are two standard models of strongly correlated electrons, provide an interesting benchmark for the physics of locally correlated systems. We study the intermediate model, mass-imbalanced Hubbard model at half-filling on a 2D square lattice which connects continuously the HM to the FKM.We employ dynamical mean field theory (DMFT) and dynamical cluster approximation (DCA) using continuous-time auxiliary field method (CT-AUX) as self-consistent impurity solver to study the single particle spectral function and self-energy allowing us to map-out the phase diagram of the system. Solutions to the mass-imbalanced model cannot enforce paramagnetic self-consistency and therefore at low temperature result in paramagnetic (PM) to antiferromagnetic (AFM) transition. In addition, in the PM state and at finite temperature, we observed a spin dependent crossover from Fermi liquid (FL) regime to non-Fermi liquid (nFL) regime in which the FL regime is destroyed, monotonically, induced not only by the interaction but also by the mass imbalance. We present the results for small cluster DCA and explore its dependency on cluster size as well.

Item Type: Thesis (Masters)
Item ID: 14012
Additional Information: Includes bibliographical references (pages 71-80).
Keywords: Condensed Matter Theory, Strongly correlated Systems, Hubbard Model
Department(s): Science, Faculty of > Physics and Physical Oceanography
Date: July 2019
Date Type: Submission
Library of Congress Subject Heading: Solid state physics; Condensed matter; Hubbard model.

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