Related papers: Large size two-hole bound states in t-J model
Long-range $(r \sim p_F^{-1} \gg lattice \ spacing)$ spin-wave exchange produces a very strong pairing of the holes. The different symmetry solutions of BCS-type equation for the superconducting gap $\Delta$ are found. The most strong…
Based on a variational approach, we propose that there are two kinds of low energy states in the t-J type models at low doping. In a quasi-particle state an unpaired spin bound to a hole with a well-defined momentum can be excited with spin…
We show that the entangled-plaquette variational ansatz can be adapted to study the two-dimensional $t-J$ model in the presence of two mobile holes. Specifically, we focus on a square lattice comprising up to $N=256$ sites in the parameter…
The hole spectral function of the t-J model on a two-dimensional semi-infinite lattice is calculated using the spin-wave and noncrossing approximations. In the case of small hole concentration and strong correlations, $t\gg J$, several…
We study one and two hole properties of the t-J model at half-filling on the square lattice using series expansion methods at T=0. The dispersion curve for one hole excitations is calculated and found to be qualitatively similar to that…
For decades, it has remained an open question, whether two dopants in the $t$--$J$ model bind in the strongly correlated regime of small spin couplings versus hopping, $J \ll t$. Here, we investigate this problem in Bethe lattice structures…
A two chain ladder model is considered described by the strong coupling $t-t^\prime-J-J^\prime$ Hamiltonian. For the case of two holes moving in a background of antiferromagnetically interacting spins, exact, analytical results are derived…
The two-hole excitation spectrum of the t-J ladder at half-filling is studied using linked-cluster series expansion methods. A rich spectrum of bound states emerges, particularly at small $t/J$. Their dispersion relations and coherence…
Clusters of the two-dimensionnal t--J model with 2 holes and up to 26 sites are diagonalized using a Lanczos algorithm. The behaviour of the binding energy with system size suggests the existence of a finite critical value of J above which…
Determination of the parameter regime in which two holes in the t-J model form a bound state represents a long standing open problem in the field of strongly correlated systems. By applying and systematically improving the exact…
We consider modified $t-J$ model with minimum of single-hole dispersion at the points $(0,\pm \pi)$, $(\pm \pi,0)$. It is shown that two holes on antiferromagnetic background produce a bound state which properties strongly differs from the…
The formation of bound states of holes in an antiferromagnetic spin-1/2 background is studied using numerical techniques applied to the ${\rm t-J}$ Hamiltonian on clusters with up to 26 sites. An analysis of the binding energy as a function…
The t-J model in the spinless-fermion representation is studied. An effective Hamiltonian for the quasiparticles is derived using canonical transformation approach. It is shown that the rather simple form of the transformation generator…
Ground state wave function of two-dimensional t-J model is found at doping close to half filling. It is shown that the condensation of Cooper pairs (superconducting pairing of mobile holes) and the condensation of spin-waves into…
We compute the ground-state fidelity and various correlations to gauge the competition between different orders in two-dimensional t-J-type models. Using exact numerical diagonalization techniques, these quantities are examined for (i) the…
The two-dimensional $t$-$J$ model in the ground state is investigated by the power Lanczos method. The pairing-pairing correlation function for $d_{x^2-y^2}$-wave symmetry is enhanced in the realistic parameter regime for high-$T_c$…
Using the description in terms of the Hubbard operators hole and spin Green's functions of the two-dimensional t-J model are calculated in an approximation which retains the rotation symmetry of the spin susceptibility in the paramagnetic…
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…
The stability of hole bound states in the t-J model including short-range Coulomb interactions is analyzed using computational techniques on ladders with up to $2 \times 30$ sites. For a nearest-neighbors (NN) hole-hole repulsion, the…
A simple variation of the Lanczos method is discussed. The new technique is based on a systematic reduction of the size of the Hilbert space of the model under consideration. As an example, the two dimensional ${\rm t-J_z}$ model of…