Current-current correlations in a CuO_3 model system

TL;DR

This study uses DMRG to analyze how nearest-neighbour repulsions affect current-current correlations in a CuO_3 model, revealing that repulsive interactions can enhance correlations and slow their decay, with implications for understanding cuprate superconductors.

Contribution

It demonstrates that repulsive interactions can significantly increase and modify the decay of current-current correlations in a CuO_3 model system, a novel insight for such models.

Findings

Repulsive interactions increase current-current correlations.

V influences the long-distance behavior of correlations.

Interactions can slow the decay of correlations over system length.

Abstract

We study a 3-band extended Hubbard model on a CuO_3 system by the density matrix renormalization group (DMRG) method. Our system has geometry similar to that of a section of the CuO_2 plane of the copper-oxide superconductors. We have studied the effects of nearest-neighbour repulsions on the current-current correlations of two model CuO_3 systems. We show that repulsive interactions are clearly capable of increasing the magnitude of the current-current correlations in both models studied. The long-distance behavior of the current-current correlations is qualitatively influenced by V. We show that repulsive interactions are capable of enhancing correlations involving at least one copper-oxygen rung over distances comparable to the length of the system. In some cases, V decreases the exponent corresponding to the power-law decay, leading to a considerable slowing down of the long-distance decay of the current-current correlations, compared to that of the Hubbard model.