Phase diagram of orbital-selective Mott transitions at finite temperatures

Mott transitions in the two-orbital Hubbard model with different bandwidths are investigated at finite temperatures. By means of the self-energy functional approach, we discuss the stability of the intermediate phase with one orbital localized and the other itinerant, which is caused by the orbital-selective Mott transition (OSMT). It is shown that the OSMT realizes two different coexistence regions at finite temperatures in accordance with the recent results of Liebsch. We further find that the particularly interesting behavior emerges around the special condition $U=U'$ and J=0, which includes a new type of the coexistence region with three distinct states. By systematically changing the Hund coupling, we establish the global phase diagram to elucidate the key role played by the Hund coupling on the Mott transitions.Mott transitions in the two-orbital Hubbard model with different bandwidths are investigated at finite temperatures. By means of the self-energy functional approach, we discuss the stability of the intermediate phase with one orbital localized and the other itinerant, which is caused by the orbital-selective Mott transition (OSMT). It is shown that the OSMT realizes two different coexistence regions at finite temperatures in accordance with the recent results of Liebsch. We further find that the particularly interesting behavior emerges around the special condition $U=U'$ and J=0, which includes a new type of the coexistence region with three distinct states. By systematically changing the Hund coupling, we establish the global phase diagram to elucidate the key role played by the Hund coupling on the Mott transitions.

arXiv:cond-mat/0506151Journal of the Physical Society of JapanSep 15, 200524 citations

Orbital-selective Mott transitions in the degenerate Hubbard model

昌久古賀, Akihisa Koga

Jan 1, 20040 citations

Finite-temperature Mott transitions in the multiorbital Hubbard model

Kensuke Inaba, Akihisa Koga, Sei-ichiro Suga +1 more

We investigate the Mott transitions in the multiorbital Hubbard model at half-filling by means of the self-energy functional approach. The phase diagrams are obtained at finite temperatures for the Hubbard model with up to fourfold degenerate bands. We discuss how the first-order Mott transition points ${U}_{c1}$ and ${U}_{c2}$ as well as the critical temperature ${T}_{c}$ depend on the orbital degeneracy. It is elucidated that enhanced orbital fluctuations play a key role to control the Mott transitions in the multiorbital Hubbard model.We investigate the Mott transitions in the multiorbital Hubbard model at half-filling by means of the self-energy functional approach. The phase diagrams are obtained at finite temperatures for the Hubbard model with up to fourfold degenerate bands. We discuss how the first-order Mott transition points ${U}_{c1}$ and ${U}_{c2}$ as well as the critical temperature ${T}_{c}$ depend on the orbital degeneracy. It is elucidated that enhanced orbital fluctuations play a key role to control the Mott transitions in the multiorbital Hubbard model.

arXiv:cond-mat/0506150Physical Review BAug 8, 200552 citations

Mott transition and Universality at finite temperatures

Stefanos Papanikolaou, Rafael M. Fernandes, Eduardo Fradkin +3 more

Bulletin of the American Physical SocietyMar 13, 20080 citations

Orbital-selective Mott transitions in two-band Hubbard models

Nils Blümer, C. Knecht, Krunoslav Požgajčić +1 more

arXiv:cond-mat/0609758Journal of Magnetism and Magnetic MaterialsNov 10, 20064 citations

Slope-reversed Mott transition in multiorbital systems

Aaram J. Kim, M. Y. Choi, Gun Sang Jeon

We examine finite-temperature phase transitions in the two-orbital Hubbard model with different bandwidths by means of the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method. It is found that there emerges a peculiar slope-reversed first-order Mott transition between the orbital-selective Mott phase and the Mott insulator phase in the presence of Ising-type Hund's coupling. The origin of the slope-reversed phase transition is clarified by the analysis of the temperature dependence of the energy density. It turns out that the increase of Hund's coupling lowers the critical temperature of the slope-reversed Mott transition. Beyond a certain critical value of Hund's coupling the first-order transition turns into a finite-temperature crossover. We also reveal that the orbital-selective Mott phase exhibits frozen local moments in the wide orbital, which is demonstrated by the spin-spin correlation functions.We examine finite-temperature phase transitions in the two-orbital Hubbard model with different bandwidths by means of the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method. It is found that there emerges a peculiar slope-reversed first-order Mott transition between the orbital-selective Mott phase and the Mott insulator phase in the presence of Ising-type Hund's coupling. The origin of the slope-reversed phase transition is clarified by the analysis of the temperature dependence of the energy density. It turns out that the increase of Hund's coupling lowers the critical temperature of the slope-reversed Mott transition. Beyond a certain critical value of Hund's coupling the first-order transition turns into a finite-temperature crossover. We also reveal that the orbital-selective Mott phase exhibits frozen local moments in the wide orbital, which is demonstrated by the spin-spin correlation functions.

arXiv:1509.01415Physical Review BSep 14, 20151 citation

U=U'

and J=0, which includes a new type of the coexistence region with three distinct states. By systematically changing the Hund coupling, we establish the global phase diagram to elucidate the key role played by the Hund coupling on the Mott transitions.

{U}_{c1}

and

{U}_{c2}

as well as the critical temperature

{T}_{c}

depend on the orbital degeneracy. It is elucidated that enhanced orbital fluctuations play a key role to control the Mott transitions in the multiorbital Hubbard model.