Ground-State Properties of the t–J Model for the CuO Double-Chain Structure

We investigate the ground-state properties of a correlated model for the double-chain structure in cuprates. We consider the t–J model, in which the nearest-neighbor spin interaction J₁ is smaller than the next-nearest neighbor interaction J₂ corresponding to the CuO double-chain structure. We vary J₁ from antiferromagnetic to ferromagnetic values and calculate the correlation functions including the superconducting pair correlation function. Employing the density-matrix renormalization group method, we show that the ground state for antiferromagnetic J₁ exhibits the hallmarks of the Luther–Emery liquid phase, in which the spin-singlet pair and charge-density-wave correlations exhibit power-law decays against distance, and the spin correlation function decays exponentially. Its signatures are gradually dismissed as J₁ approaches the ferromagnetic regime. Our findings suggest that the antiferromagnetic double-chain structure without ferromagnetic bonds is favorable for superconductivity.