Various ordered states in a 2D interacting electron system close to an electronic topological transition

TL;DR

This paper investigates various ordered states, including density waves and superconductivity, in a 2D electron system near a topological transition, revealing a complex phase diagram relevant to high-Tc cuprates.

Contribution

It introduces a comprehensive analysis of multiple competing orders and their coexistence in a 2D electron system near a topological transition, including a new phase diagram with mixed phases.

Findings

Existence of density wave and d-wave superconducting instabilities near the critical point.

Coexistence of dSC and SDW orders implies a third pi triplet superconducting order.

A new phase diagram with mixed SDW, dSC, and PTS phases is proposed.

Abstract

We consider a 2D electron system on a square lattice with hopping beyond nearest neighbors. The existence of the quantum critical point associated with an electronic topological transition in the noninteracting system results in density wave (DW) and high temperature d-wave superconducting (dSC) instabilities in the presence of an exchange interaction J. We analyse different DW ordering such as isotropic Spin DW (SDW), d-wave SDW, isotropic Charge DW (CDW) and d-wave CDW. The coexistence of dSC and SDW orders leads necessary to the existence of a third order which is a pi triplet superconducting (PTS) order. A new phase diagram with a mixed phase of SDW, dSC and PTS order is found. The theory is applied to high-Tc cuprates.