The Metal-Insulator Transition in the Doubly Degenerate Hubbard Model

Дата и время публикации : 1997-04-20T23:18:55Z

Авторы публикации и институты :
Hideo Hasegawa (Tokyo Gakugei Univ.)

Ссылка на журнал-издание: J. Phys. Soc. Jpn. 66 (1997) 3522-3527
Коментарии к cтатье: Latex 16 pages, 10 ps figures included, published in J. Phys. Soc. Jpn. with some minor modifications. (
Первичная категория: cond-mat.str-el

Все категории : cond-mat.str-el

Краткий обзор статьи: 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 $Sr_{1-x}La_xTiO_3$ which is reported to significantly increase as $x$ approaches unity.

Category: Physics