Spin-Triplet Pairing Induced by Near-Neighbor Attraction in the Cuprate Chain

Abstract

In quantum materials, the electronic interaction and the electron-phonon coupling are in general two essential ingredients, the combined impact of which may drive exotic phases. Recently, an anomalously strong electron-electron attraction, mediated by phonons, has been unveiled in one-dimensional (1D) copper-oxide chain compound [1,2]. Yet it is unclear how this strong near-neighbor (NN) attraction V influences the superconductivity pairing. In this work, we employ the density-matrix renormalization group (DMRG) method to study this experiment-relevant extended Hubbard model with on-site Coulomb repulsion U > 0 and NN attraction V < 0, relevant for the 1D cuprate chain and likely other similar transition-metal materials. We find this extended t-U -V model hosts a rich quantum phase diagram consisting of the spin density wave phase, phase separation phases, the Tomonaga-Luttinger liquid (TLL) phase, and especially an intriguing TLL regime with divergent superconducting susceptibility and dominant spin-triplet pair correlations. Upon doping, such a spin-triplet pairing regime can be further broadened in the parameter space and extends to larger U . Our results show robust triplet pairing induced by attractive interaction V , offering a feasible mechanism to realize p-wave superconductivity in 1D cuprates.

Superconducting Phases of the Square-Lattice Extended Hubbard Model

“…In mean-field calculations [38], the two phases could possibly coexist. This is consistent with the dominance of the p-wave instability in 1D systems [28,29,33], where the d-FIG. 9.…”

“…A repulsive V can induce a charge density wave (CDW), and an attractive V was argued to favor spin-triplet superconductivity [28,29]. Already in 1D systems, a p-wave superconducting phase was predicted for repulsive U and attractive V in EHM [30][31][32][33]. Similar studies have been explored in 2D systems [34][35][36][37][38][39], using weak-coupling theory or with approximation in treating interaction effect.…”

Quantum correlations, entanglement spectrum and coherence of two-particle reduced density matrix in the Extended Hubbard Model

“…Many efforts have been devoted to the investigation of the phase diagram of the EHM at half filling, with methods ranging from analytical, pertubative, approximations based on bosonization as well as numerical ones [76][77][78][79][80][81][82][83][84][85][86]. Despite the apparent simplicity of the model it is predicted to exhibit a very rich phase diagram.…”

Determinant quantum Monte Carlo for the half-filled Hubbard model with nonlocal density-density interactions

“…Nonlocal Coulomb interactions are also argued to be important in graphene 8 because of poor screening, and in magicangle twisted bilayer graphene 9 because of the peculiar three-lobe Wannier functions for the low energy electron degrees of freedom [10][11][12] . These progresses renew the interest in the extended Hubbard model with the on-site Hubbard U and density-density interactions V on neighboring bonds [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] .…”