arXiv:cond-mat/0107202 · Journal of the Physical Society of Japan

Critical Behaviour near the Mott Metal–Insulator Transition in a Two-Band Hubbard Model

Yasuo Ohashi, Yoshiaki Ōno

Published Oct 1, 2001• 12 citations

arXiv HTML PDF

Abstract

DOI: 10.1143/jpsj.70.2989

Related papers

Critical Behaviour near the Mott Transition in a Two-Band Hubbard Model

Ohashi, Yasuo, Yoshiaki Ōno

arXiv:cond-mat/0109446Sep 25, 20010 citations

Effect of Direct Transfer on Critical Behaviour of Mott Transition in the Two-Band Hubbard Model

Yasuo Ohashi, Yoshiaki Ōno

Journal of the Physical Society of JapanJan 1, 20024 citations

Magnetism and Superconductivity in a Two-band Hubbard Model in Infinite Dimensions

Yoshiaki Ōno, Kazuhiro Sano

arXiv:cond-mat/0304624Journal of the Physical Society of JapanJan 1, 20021 citation

Assessing the orbital selective Mott transition with variational wave functions

Luca F. Tocchio, Federico Arrigoni, Sandro Sorella +1 more

arXiv:1505.07006Journal of Physics Condensed MatterFeb 16, 201616 citations

Mott transitions in correlated electron systems with orbital degrees of freedom

Yūichi Ono, Michael Potthoff, R. Bulla

arXiv:cond-mat/0206508Physical review. B, Condensed matterJan 30, 200380 citations

Mott transition in correlated electron systems with orbital degree of freedom

Yoshiaki Ōno, R. Bulla, Michael Potthoff

Jan 1, 20030 citations

arXiv:cond-mat/0107202 · Journal of the Physical Society of Japan

Critical Behaviour near the Mott Metal–Insulator Transition in a Two-Band Hubbard Model

Yasuo Ohashi, Yoshiaki Ōno

Published Oct 1, 2001• 12 citations

arXiv HTML PDF

Abstract

U

at the

d

-orbital and the charge-transfer energy

Δ

between the

d

- and

p

-orbitals. Critical behaviour of the quasiparticle weight is also obtained analytically as a function of

U

and

Δ

. The analytic results are in good agreement with the numerical results of the exact diagonalization method.

DOI: 10.1143/jpsj.70.2989

Related papers

Critical Behaviour near the Mott Transition in a Two-Band Hubbard Model

Ohashi, Yasuo, Yoshiaki Ōno

The Mott metal-insulator transition in the two-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The discontinuity in the chemical potential for the change from hole to electron doping is calculated analytically as a function of the on-site Coulomb interaction $U$ , and the charge-transfer energy $Δ$ between the $d$ - and $p$ -orbitals, transfer integrals $t_{pd}$ , $t_{pp}$ , $t_{dd}$ between $p$ - $d$ , $p$ - $p$ and $d$ - $d$ sites respectively. The critical behaviour of the quasiparticle weight is also obtained analytically.The Mott metal-insulator transition in the two-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The discontinuity in the chemical potential for the change from hole to electron doping is calculated analytically as a function of the on-site Coulomb interaction $U$, and the charge-transfer energy $Δ$ between the $d$- and $p$-orbitals, transfer integrals $t_{pd}$, $t_{pp}$, $t_{dd}$ between $p$-$d$, $p$-$p$ and $d$-$d$ sites respectively. The critical behaviour of the quasiparticle weight is also obtained analytically.

arXiv:cond-mat/0109446Sep 25, 20010 citations

Effect of Direct Transfer on Critical Behaviour of Mott Transition in the Two-Band Hubbard Model

Yasuo Ohashi, Yoshiaki Ōno

The Mott metal–insulator transition in the two-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The discontinuity in the chemical potential for the change from hole to electron doping is calculated analytically as a function of the on-site Coulomb interaction U , and the charge-transfer energy Δ between the d - and p -orbitals, transfer integrals t p d , t p p , t d d between p – d , p – p , and d – d sites respectively. The critical behaviour of the quasiparticle weight is also obtained analytically.The Mott metal–insulator transition in the two-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The discontinuity in the chemical potential for the change from hole to electron doping is calculated analytically as a function of the on-site Coulomb interaction U , and the charge-transfer energy Δ between the d - and p -orbitals, transfer integrals t p d , t p p , t d d between p – d , p – p , and d – d sites respectively. The critical behaviour of the quasiparticle weight is also obtained analytically.

Journal of the Physical Society of JapanJan 1, 20024 citations

Magnetism and Superconductivity in a Two-band Hubbard Model in Infinite Dimensions

Yoshiaki Ōno, Kazuhiro Sano

We study a two-band Hubbard model using the dynamical mean-field theory combined with the exact diagonalization method. At the electron density $n=2$ , a transition from a band-insulator to a correlated semimetal occurs when the on-site Coulomb interaction $U$ is varied for a fixed value of the charge-transfer energy $Δ$ . At low temperature, the correlated semimetal shows ferromagnetism or superconductivity. With increasing doping $|n-2|$ , the ferromagnetic transition temperature rapidly decreases and finally becomes zero at a critical value of $n$ . The second-order phase transition occurs at high temperature, while a phase separation of ferromagnetic and paramagnetic states takes place at low temperature. The superconducting transition temperature gradually decreases and finally becomes zero near $n=1$ ( $n=3$ ) where the system is Mott insulator which shows antiferromagnetism at low temperature.We study a two-band Hubbard model using the dynamical mean-field theory combined with the exact diagonalization method. At the electron density $n=2$, a transition from a band-insulator to a correlated semimetal occurs when the on-site Coulomb interaction $U$ is varied for a fixed value of the charge-transfer energy $Δ$. At low temperature, the correlated semimetal shows ferromagnetism or superconductivity. With increasing doping $|n-2|$, the ferromagnetic transition temperature rapidly decreases and finally becomes zero at a critical value of $n$. The second-order phase transition occurs at high temperature, while a phase separation of ferromagnetic and paramagnetic states takes place at low temperature. The superconducting transition temperature gradually decreases and finally becomes zero near $n=1$ ($n=3$) where the system is Mott insulator which shows antiferromagnetism at low temperature.

arXiv:cond-mat/0304624Journal of the Physical Society of JapanJan 1, 20021 citation

Assessing the orbital selective Mott transition with variational wave functions

Luca F. Tocchio, Federico Arrigoni, Sandro Sorella +1 more

We study the Mott metal-insulator transition in the two-band Hubbard model with different hopping amplitudes t1 and t2 for the two orbitals on the two-dimensional square lattice by using non-magnetic variational wave functions, similarly to what has been considered in the limit of infinite dimensions by dynamical mean-field theory. We work out the phase diagram at half filling (i.e. two electrons per site) as a function of R = t2/t1 and the on-site Coulomb repulsion U, for two values of the Hund's coupling J = 0 and J/U = 0.1. Our results are in good agreement with previous dynamical mean-field theory calculations, demonstrating that the non-magnetic phase diagram is only slightly modified from infinite to two spatial dimensions. Three phases are present: a metallic one, for small values of U, where both orbitals are itinerant; a Mott insulator, for large values of U, where both orbitals are localized because of the Coulomb repulsion; and the so-called orbital-selective Mott insulator (OSMI), for small values of R and intermediate Us, where one orbital is localized while the other one is still itinerant. The effect of the Hund's coupling is two-fold: on one side, it favors the full Mott phase over the OSMI; on the other side, it stabilizes the OSMI at larger values of R.We study the Mott metal-insulator transition in the two-band Hubbard model with different hopping amplitudes t1 and t2 for the two orbitals on the two-dimensional square lattice by using non-magnetic variational wave functions, similarly to what has been considered in the limit of infinite dimensions by dynamical mean-field theory. We work out the phase diagram at half filling (i.e. two electrons per site) as a function of R = t2/t1 and the on-site Coulomb repulsion U, for two values of the Hund's coupling J = 0 and J/U = 0.1. Our results are in good agreement with previous dynamical mean-field theory calculations, demonstrating that the non-magnetic phase diagram is only slightly modified from infinite to two spatial dimensions. Three phases are present: a metallic one, for small values of U, where both orbitals are itinerant; a Mott insulator, for large values of U, where both orbitals are localized because of the Coulomb repulsion; and the so-called orbital-selective Mott insulator (OSMI), for small values of R and intermediate Us, where one orbital is localized while the other one is still itinerant. The effect of the Hund's coupling is two-fold: on one side, it favors the full Mott phase over the OSMI; on the other side, it stabilizes the OSMI at larger values of R.

arXiv:1505.07006Journal of Physics Condensed MatterFeb 16, 201616 citations

Mott transitions in correlated electron systems with orbital degrees of freedom

Yūichi Ono, Michael Potthoff, R. Bulla

Mott metal-insulator transitions in an M-fold orbitally degenerate Hubbard model are studied by means of a generalization of the linearized dynamical mean-field theory. The method allows for an efficient and reliable determination of the critical interaction ${U}_{\mathrm{c}}$ for any integer filling n and different M at zero temperature. For half filling a linear dependence of ${U}_{\mathrm{c}}$ on M is found. Inclusion of the (full) Hund's rule exchange J results in a strong reduction of ${U}_{\mathrm{c}}.$ The transition turns out to change qualitatively from continuous for $J=0$ to discontinuous for any finite J. This result is confirmed using the exact-diagonalization method for $M=2.$ Mott metal-insulator transitions in an M-fold orbitally degenerate Hubbard model are studied by means of a generalization of the linearized dynamical mean-field theory. The method allows for an efficient and reliable determination of the critical interaction ${U}_{\mathrm{c}}$ for any integer filling n and different M at zero temperature. For half filling a linear dependence of ${U}_{\mathrm{c}}$ on M is found. Inclusion of the (full) Hund's rule exchange J results in a strong reduction of ${U}_{\mathrm{c}}.$ The transition turns out to change qualitatively from continuous for $J=0$ to discontinuous for any finite J. This result is confirmed using the exact-diagonalization method for $M=2.$

arXiv:cond-mat/0206508Physical review. B, Condensed matterJan 30, 200380 citations

Mott transition in correlated electron systems with orbital degree of freedom

Yoshiaki Ōno, R. Bulla, Michael Potthoff

Mott metal-insulator transitions in an M-fold orbitally degenerate Hubbard model are studied by means of a generalization of the linearized dynamical mean-field theory. The method allows for an efficient and reliable determination of the critical interaction Uc for any integer filling n and different M at zero temperature. For half-filling a linear dependence of Uc on M is found. Inclusion of the (full) Hund's rule exchange J results in a strong reduction of Uc. The transition turns out to change qualitatively from continuous for J=0 to discontinuous for any finite J. This result is confirmed using the exact-diagonalization method for M=2.Mott metal-insulator transitions in an M-fold orbitally degenerate Hubbard model are studied by means of a generalization of the linearized dynamical mean-field theory. The method allows for an efficient and reliable determination of the critical interaction Uc for any integer filling n and different M at zero temperature. For half-filling a linear dependence of Uc on M is found. Inclusion of the (full) Hund's rule exchange J results in a strong reduction of Uc. The transition turns out to change qualitatively from continuous for J=0 to discontinuous for any finite J. This result is confirmed using the exact-diagonalization method for M=2.

Jan 1, 20030 citations

U

at the

d

-orbital and the charge-transfer energy

Δ

between the

d

- and

p

-orbitals. Critical behaviour of the quasiparticle weight is also obtained analytically as a function of

U

and

Δ

. The analytic results are in good agreement with the numerical results of the exact diagonalization method.

U

, and the charge-transfer energy

Δ

between the

d

- and

p

-orbitals, transfer integrals

t_{pd}

t_{pp}

t_{dd}

between

p

d

p

p

and

d

d

sites respectively. The critical behaviour of the quasiparticle weight is also obtained analytically.

We study a two-band Hubbard model using the dynamical mean-field theory combined with the exact diagonalization method. At the electron density

n=2

, a transition from a band-insulator to a correlated semimetal occurs when the on-site Coulomb interaction

U

is varied for a fixed value of the charge-transfer energy

Δ

. At low temperature, the correlated semimetal shows ferromagnetism or superconductivity. With increasing doping

|n-2|

, the ferromagnetic transition temperature rapidly decreases and finally becomes zero at a critical value of

n

. The second-order phase transition occurs at high temperature, while a phase separation of ferromagnetic and paramagnetic states takes place at low temperature. The superconducting transition temperature gradually decreases and finally becomes zero near

n=1

(

n=3

) where the system is Mott insulator which shows antiferromagnetism at low temperature.

{U}_{\mathrm{c}}

for any integer filling n and different M at zero temperature. For half filling a linear dependence of

{U}_{\mathrm{c}}

on M is found. Inclusion of the (full) Hund's rule exchange J results in a strong reduction of

{U}_{\mathrm{c}}.

The transition turns out to change qualitatively from continuous for

J=0

to discontinuous for any finite J. This result is confirmed using the exact-diagonalization method for

M=2.