Related papers: Superconductivity in the Two-Dimensional $t$-$J$ M…
The phase diagram of the two-dimensional t-J model is determined accurately at low electron density by a combination of analytic and numerical techniques. The ground state exhibits three phases in the limit of zero electron density: an…
Motivated by recent neutron scattering and scanning tunneling microscopy (STM) experiments on cuprate superconductors, we discuss charge-ordered states, in particular with two-dimensional charge modulation patterns, co-existing with…
We investigate the phase diagram of the two-dimensional t-J model using a recently developed Green's Function Monte Carlo method for lattice fermions. We use the technique to calculate exact ground-state energies of the model on large…
Two-leg t-J ladders are investigated in the framework of a combination of the phase string formulation and bond-operator representation. We develope a mean-field theory in the strong rung interaction regime, i.e. $J_{\perp}\gg J, t$, which…
We study the honeycomb lattice $t$-$J$ model using the fermionic tensor network approach. By examining the ansatz with various unit cells, we discover several different stripe states with different periods that compete strongly with uniform…
Extensive numerical studies have demonstrated that the two-dimensional single-band Hubbard model contains much of the key physics in cuprate high-temperature superconductors. However, there is no definitive proof that the Hubbard model…
We study a ground-state ansatz for the single-hole doped $t$-$J$ model in two dimensions via a variational Monte Carlo (VMC) method. Such a single-hole wave function possesses finite angular momenta generated by hidden spin currents, which…
The one-dimensional (1D) $t$-$J$ model is investigated by using a Gutzwiller-Jastrow-type variation method and the exact diagonalization of small systems. Variational expectation values are estimated by the variational Monte Carlo method…
We have numerically investigated the doped t-J ladder using exact diagonalization. We have studied both the limit of strong inter-chain coupling and isotropic coupling. The ladder scales to the Luther-Emery liquid regime in the strong…
In nonperturbative regimes, the superfluid instability in the two-dimensional Hubbard model can be described by an emergent BCS theory with small effective pairing constants. We compute the effective couplings using a controlled bold-line…
We report results of a study of strongly correlated $d$-wave superconducting slabs within a t-J model solved using the statistically consistent Gutzwiller approach. For different dopings, we model slabs cut at 45$^\circ$ relative to the…
Disorder and doping have profound effects on the intrinsic physical mechanisms of superconductivity. In this paper, we employed the determinant quantum Monte Carlo method to investigate the symmetry-allowed superconducting orders on the…
The two-dimensional t-J model on a frustrating lattice is studied using mean-field variational theories with Gutzwiller approximation. We find that a superconducting state with broken time-reversal symmetry (d+id state) is realized in the…
We study the evolution of the optical conductivity in the t-J model with temperature and doping using the Extended Dynamical Cluster Approximation. The cluster approach results in an optical mass which is doping independent near half…
The local density of states (LDOS) around a magnetic impurity in high-Tc superconductors is studied using the two-dimensional t-J model with a realistic band structure. The order parameters are determined in a self-consistent way within the…
We investigate superconductivity in a two-band $t$-$J$ model consisting of an itinerant orbital (orbital-0) and a quasi-localized orbital (orbital-1) using variational Monte Carlo. A robust orbital-selective $d$-wave superconducting state…
The one-dimensional t-J model with density-density repulsive interactions is investigated using exact diagonalization and quantum Monte Carlo methods. A short-range repulsion pushes phase separation to larger values of J/t, and leads to a…
Despite the intense theoretical and experimental effort, an understanding of the superconducting pairing mechanism of the high-temperature superconductors, leading to an unprecedented high transition temperature $T_c$, is still lacking.…
By means of the Lanczos method we analyze superconducting correlations in ultrasmall grains at fixed particle number. We compute the ground state properties and the excitation gap of the pairing Hamiltonian as a function of the level…
Quantum Monte Carlo method is used to re-examine superconductivity in the single-band Hubbard model in two dimensions. Instead of the conventional pairing, we consider a `correlated pairing', $\langle \tilde{c}_{i\uparrow}…