Phase diagram of the asymmetric Hubbard model

Abstract

The ground-state phase diagram of the asymmetric Hubbard model is studied in one and two dimensions by a well-controlled numerical method. The method allows to calculate directly the probabilities of particular phases in the approximate ground-state and thus to specify the stability domains corresponding to phases with the highest probabilities. Depending on the electron filling $n$ and the magnitude of the asymmetry $t_f/t_d$ between the hopping integrals of $f$ and $d$ electrons two different scenarios in formation of ground states are observed. At low electron fillings ($n\le 1/3$) the ground states are always phase segregated in the limit of strong asymmetry ($t_d\gg t_f$). With decreasing asymmetry the system undergoes a transition to the phase separated state and then to the homogeneous state. For electron fillings $n>1/3$ and weak Coulomb interactions the ground state is homogeneous for all values of asymmetry, while for intermediate and strong interactions the system exhibits the same sequence of phase transitions as for $n$ small. Moreover, it is shown that the segregated phase is significantly stabilized with increasing electron filling, while the separated phases disappear gradually from the ground-state phase diagrams.

arXiv comment10 pages, 5 figures

References in corpus (7)

• Electronic Ferroelectricity in the Falicov-Kimball Model
• Intermediate Coupling Theory of Electronic Ferroelectricity
• Phase separation due to quantum mechanical correlations
• Segregation in the asymmetric Hubbard model
• The ground state of a mixture of two species of fermionic atoms in 1D optical lattice
• Bosonization study of quantum phase transitions in the one-dimensional asymmetric Hubbard model
• Spectral functions of the Falicov-Kimball model with electronic ferroelectricity

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• Anomalous resistivity and the electron-polaron effect in the two-band Hubbard model with one narrow band
• Mass-Imbalanced Ionic Hubbard Chain
• Ground-state properties of fermionic mixtures with mass imbalance in optical lattices
• Effective Hamiltonian for a Half-filled Asymmetric Ionic Hubbard Chain with Alternating On-site Interaction
• Itinerant ferromagnetism in narrow-band metals
• Infinite temperature spin dynamics in the asymmetric Hatsugai-Kohmoto model
• Excitonic Insulator and the Extended Falicov--Kimball Model Away from Half-Filling
• Anomalous Quantum Relaxation in the Infinite Temperature Hubbard Chain