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Superconducting, Ferromagnetic and Antiferromagnetic Phases in thet-t′Hubbard Model

Jose Vicente Alvarez, J. González, F. Guinea +1 more

We apply a renormalization group approach to the determination of the phase diagram of the t-t' Hubbard model at the Van Hove filling, as function of t'/t, for small values of U/t. The model presents ferromagnetic, antiferromagnetic and d-wave superconducting phases. Antiferromagnetism and d-wave superconductivity arise from the same interactions, and compete in the same region of parameter space.

arXiv:cond-mat/9705165Journal of the Physical Society of JapanJun 15, 199839 citations

Antiferromagnetism, ferromagnetism and superconductivity in the Hubbard model with repulsion

Victor Nikolaevich Popov

Journal of Mathematical SciencesDec 1, 19921 citation

Absence of Ferromagnetism or Antiferromagnetism in the One- and Two-Dimensional Extended Hubbard Models

Akiomi Mishima

金沢工業大学研究紀要 AJan 1, 19780 citations

Spin-Triplet Pairing Induced by Hund's Rule Exchange in Orbitally Degenerate Systems: Hartree-Fock Approximation

M. Zegrodnik, Józef Spałek

We discuss the spin-triplet pairing mechanism induced by the Hund rule ferromagnetic exchange.We include explicitly the eect of interband hybridization and treat the problem by starting from an extended Hubbard model for a doubly degenerate band, making the simplest HartreeFock approximation for the part involving the pairing and the Hubbard interaction.The conditions of stability of various phases are determined as a function of both band lling and microscopic parameters.The phase diagram contains regions of stability of the spin-triplet superconducting phase coexisting with either saturated or non-saturated ferromagnetism.Phase diagrams for the cases of constant density of states and that of square lattice have been provided.The inuence of hybridization on the stability of considered phases, as well as the temperature dependences of magnetic moment and the superconducting gap are also discussed.We discuss the spin-triplet pairing mechanism induced by the Hund rule ferromagnetic exchange.We include explicitly the eect of interband hybridization and treat the problem by starting from an extended Hubbard model for a doubly degenerate band, making the simplest HartreeFock approximation for the part involving the pairing and the Hubbard interaction.The conditions of stability of various phases are determined as a function of both band lling and microscopic parameters.The phase diagram contains regions of stability of the spin-triplet superconducting phase coexisting with either saturated or non-saturated ferromagnetism.Phase diagrams for the cases of constant density of states and that of square lattice have been provided.The inuence of hybridization on the stability of considered phases, as well as the temperature dependences of magnetic moment and the superconducting gap are also discussed.

Acta Physica Polonica AMay 1, 20122 citations

Phase separation in the Hubbard model

Antonis N. Andriotis, Eleftherios N. Economou, Qiming Li +1 more

We use the correlated-random-field approximation and a conditional coherent-potential approximation to study the ground-state phase diagram of the one-band Hubbard model. Our approach incorporates both spin and electron correlations. It has been found that for certain values of the parameters of the model, in addition to paramagnetic, ferromagnetic, antiferromagnetic, and spin-glass or spin-liquid phases found in our earlier studies, a phase-separated phase is found to be favored for 0.7\ensuremath{\le}n\ensuremath{\le}1.0 and U/B\ensuremath{\ge}2 in good agreement with results obtained in the t-J model using the technique of the 1/N expansion. The present approach also allows one to watch the dependence of the electron density of states on the number of electrons per site and gives a single physical picture for the occurrence of a metal-insulator transition. Implications of these results for the existence of superconducting ground state as well as comparison to other studies will be briefly discussed.We use the correlated-random-field approximation and a conditional coherent-potential approximation to study the ground-state phase diagram of the one-band Hubbard model. Our approach incorporates both spin and electron correlations. It has been found that for certain values of the parameters of the model, in addition to paramagnetic, ferromagnetic, antiferromagnetic, and spin-glass or spin-liquid phases found in our earlier studies, a phase-separated phase is found to be favored for 0.7\ensuremath{\le}n\ensuremath{\le}1.0 and U/B\ensuremath{\ge}2 in good agreement with results obtained in the t-J model using the technique of the 1/N expansion. The present approach also allows one to watch the dependence of the electron density of states on the number of electrons per site and gives a single physical picture for the occurrence of a metal-insulator transition. Implications of these results for the existence of superconducting ground state as well as comparison to other studies will be briefly discussed.

Physical review. B, Condensed matterApr 15, 199322 citations

Coexistence of Superconductivity and Antiferromagnetism in the Two‐Dimensional Extended Hubbard Model with Inter‐Site Attraction

P. Wróbel

physica status solidi (b)Jun 1, 19891 citation

Superconductivity, ferromagnetism, and antiferromagnetism in the Hubbard model

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Superconductivity, ferromagnetism, and antiferromagnetism in the Hubbard model

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