Instability toward Formation of Quasi-One-Dimensional Fermi Surface in Two-Dimensional t-J Model

TL;DR

This paper demonstrates an intrinsic tendency in the 2D t-J model to form a quasi-one-dimensional Fermi surface, which can coexist with d-wave pairing under certain anisotropic conditions, relevant to cuprate superconductors.

Contribution

It reveals a hidden quasi-one-dimensional Fermi surface instability in the 2D t-J model and shows how anisotropy can induce coexistence with d-wave pairing.

Findings

Quasi-1D Fermi surface instability exists in the 2D t-J model.

Small anisotropy reveals the coexistence of q-1d state and d-wave pairing.

Coexistence may occur in La_{2-x}Sr_{x}CuO_4 systems.

Abstract

We show within the slave-boson mean field approximation that the two-dimensional t-J model has an intrinsic instability toward forming a quasi-one-dimensional (q-1d) Fermi surface. This q-1d state competes with, and is overcome by, the d-wave pairing state for a realistic parameter choice. However, we find that a small spatial anisotropy in t and J exposes the q-1d instability which has been hidden behind the d-wave pairing state, and brings about the coexistence with the d-wave pairing. We argue that this coexistence can be realized in La_{2-x}Sr_{x}CuO_4 systems