The t–J model with a prohibition of “doubles” (doubly occupied sites) in the lower Hubbard band and holes in the upper band is considered in the regime of strong electron correlations. The specific features of the electronic states are described. An expression is obtained for the transverse dynamic susceptibility χ as a function of wave vector q and frequency ω in the random phase approximation (RPA) in the metallic state of the system, and the static susceptibility (ω=0) is analyzed in the limits q=0 and q=Q=(π,π) in a square lattice as a function of the electron density n. The insulating limit (n→1) is described as a spin liquid (SL) state. An expression for the magnetic susceptibility is proposed which unifies the RPA and the SL concept in the presence of site percolation. It is shown that in a certain concentration region the static susceptibility is negative (i.e., a diamagnetic effect), which indicates the possibility of a superconducting state with an exchange mechanism of pairing.The t–J model with a prohibition of “doubles” (doubly occupied sites) in the lower Hubbard band and holes in the upper band is considered in the regime of strong electron correlations. The specific features of the electronic states are described. An expression is obtained for the transverse dynamic susceptibility χ as a function of wave vector q and frequency ω in the random phase approximation (RPA) in the metallic state of the system, and the static susceptibility (ω=0) is analyzed in the limits q=0 and q=Q=(π,π) in a square lattice as a function of the electron density n. The insulating limit (n→1) is described as a spin liquid (SL) state. An expression for the magnetic susceptibility is proposed which unifies the RPA and the SL concept in the presence of site percolation. It is shown that in a certain concentration region the static susceptibility is negative (i.e., a diamagnetic effect), which indicates the possibility of a superconducting state with an exchange mechanism of pairing.

Low Temperature PhysicsFeb 1, 20051 citation

Dynamic spin susceptibility in thet-J model

G. Dzhakeli, Nikolay M. Plakida

Theoretical and Mathematical PhysicsMar 1, 199810 citations

Long-range orders and spin/orbital freezing in the two-band Hubbard model

Karim Steiner, Shintaro Hoshino, Yusuke Nomura +1 more

We solve the orbitally degenerate two-band Hubbard model within dynamical mean field theory and map out the instabilities to various symmetry-broken phases based on an analysis of the corresponding lattice susceptibilities. Phase diagrams as a function of the Hund coupling parameter $J$ are obtained both for the model with rotationally invariant interaction and for the model with Ising-type anisotropy. For negative $J$ , an intraorbital spin-singlet superconducting phase appears at low temperatures, while the normal state properties are characterized by an orbital-freezing phenomenon. This is the $\text{negative-}J$ analog of the recently discovered fluctuating-moment induced $s\text{-wave}$ spin-triplet superconductivity in the spin-freezing regime of multiorbital models with $J>0$ .We solve the orbitally degenerate two-band Hubbard model within dynamical mean field theory and map out the instabilities to various symmetry-broken phases based on an analysis of the corresponding lattice susceptibilities. Phase diagrams as a function of the Hund coupling parameter $J$ are obtained both for the model with rotationally invariant interaction and for the model with Ising-type anisotropy. For negative $J$, an intraorbital spin-singlet superconducting phase appears at low temperatures, while the normal state properties are characterized by an orbital-freezing phenomenon. This is the $\text{negative-}J$ analog of the recently discovered fluctuating-moment induced $s\text{-wave}$ spin-triplet superconductivity in the spin-freezing regime of multiorbital models with $J>0$.

arXiv:1605.06410Physical review. B./Physical review. BAug 3, 201629 citations

Dynamic spin susceptibility in the planar t − J model at finite temperatures

Janez Jaklič, Peter Prelovšek

Physica C SuperconductivityDec 1, 19940 citations

J

are obtained both for the model with rotationally invariant interaction and for the model with Ising-type anisotropy. For negative

J

, an intraorbital spin-singlet superconducting phase appears at low temperatures, while the normal state properties are characterized by an orbital-freezing phenomenon. This is the

\text{negative-}J

analog of the recently discovered fluctuating-moment induced

s\text{-wave}

spin-triplet superconductivity in the spin-freezing regime of multiorbital models with

J>0