The Metal-Insulator Transition in the Doubly Degenerate Hubbard Model

Abstract

A systematic study has been made on the metal-insulator (MI) transition of the doubly degenerate Hubbard model (DHM) in the paramagnetic ground state, by using the slave-boson mean-field theory which is equivalent to the Gutzwiller approximation (GA). For the case of infinite electron-electron interactions, we obtain the analytic solution, which becomes exact in the limit of infinite spatial dimension. On the contrary, the finite-interaction case is investigated by numerical methods with the use of the simple-cubic model with the nearest-neighbor hopping. The mass-enhancement factor, $Z$, is shown to increase divergently as one approaches the integer fillings ($N=1,2,3$), at which the MI transition takes place, $N$ being the total number of electrons. The calculated $N$ dependence of $Z$ is compared with the observed specific-heat coefficient, $\gamma$, of $S{r}_{1-x}L{a}_{x}Ti{O}_3$ which is reported to significantly increase as $x$ approaches unity.

Latex 16 pages, 10 ps figures included, published in J. Phys. Soc. Jpn. with some minor modifications. ([email protected])

References in corpus (1)

• Slave-Boson Mean-Field Theory of the Antiferromagnetic State in the Doubly Degenerate Hubbard Model - the Half-Filled Case -

Cited by in corpus (5)

• Equivalence of Gutzwiller and slave-boson mean-field theories for multi-band Hubbard models
• Metal-insulator transition in the two-orbital Hubbard model at fractional band fillings: Self-energy functional approach
• Phase diagram of orbital-selective Mott transitions at finite temperatures
• Filling-driven Mott transition in SU(N) Hubbard models
• Numerical Study for the Ground State of Multi-Orbital Hubbard Models