Competing orders and the doping and momentum dependent quasiparticle excitations in cuprate superconductors

TL;DR

This paper investigates low-energy quasiparticle excitations in cuprate superconductors, revealing that their doping and momentum dependence support a coexistence of competing orders, such as charge-density and spin-density waves, with superconductivity.

Contribution

It provides experimental and theoretical evidence for competing orders coexisting with superconductivity in cuprates, challenging the $d$-density wave scenario.

Findings

Quasiparticle spectra are consistent with coexisting competing orders and superconductivity.

Vortex-state spectroscopy reveals pseudogap-like features indicating competing order inside vortex cores.

Spectral characteristics favor charge- and spin-density waves over $d$-density wave as competing orders.

Abstract

The low-energy quasiparticle excitations in hole- and electron-type cuprate superconductors are investigated via both experimental and theoretical means. It is found that the doping and momentum dependence of the empirical low-energy quasiparticle excitations is consistent with a scenario of coexisting competing orders and superconductivity in the ground state of the cuprates. This finding, based on zero-field quasiparticle spectra, is further corrobarated by the patially resolved vortex-state scanning tunneling spectroscopy, which reveals pseudogap-like features consistent with a remaining competing order inside the vortex core upon the suppression of superconductivity. The competing orders compatible with empirical observations include the charge-density wave and spin-density wave. In contrast, spectral characteristics derived from incorporating the $d$-density wave as a competing order appear unfavorable in comparison with experiments.