Intrinsic Hallmarks of Phonon-Induced Charge Order in Cuprates

TL;DR

This paper proposes that phonon interactions with electronic correlations induce charge density waves in underdoped cuprates, reconstructing the Fermi surface and matching experimental quantum oscillation data.

Contribution

It introduces a phonon-induced mechanism for charge order in cuprates, explaining Fermi surface reconstruction and intra-unit-cell charge modulations.

Findings

Fermi surface reconstructed with electron and hole pockets

Charge modulations are predominantly s-wave

Quantum oscillation frequencies align with experiments

Abstract

Charge-density wave (CDW) modulations in underdoped high-temperature cuprate superconductors remain a central puzzle in condensed matter physics. However, despite a substantial experimental verification of this ubiquitous phase in a large class of high $T_{\mathrm{c}}$ cuprates, a complete theoretical explanation of this phase is still missing. Here, we build upon our recent proposal that the CDW in underdoped cuprates (Y- and Bi- based compounds) emerges from a unique cooperation of the B$_{1g}$ bond-buckling phonon with strong electronic correlations. We assume a static mean-field lattice distortion with B$_{1g}$ symmetry, regardless of its origin, with a commensurate wave vector $\mathbf{q}^*=(2\pi/3,0)/(0,2\pi/3)$. We show that such a phonon-induced CDW (both uni- and bi-axial) reconstructs the Fermi surface, leading to electron and hole pockets, with relevant quantum oscillation frequencies in close consistency with the experiments. Furthermore, a systematic analysis of the symmetry of the intra-unit-cell charge modulations on the copper-oxygen planes is provided. We find that the atomic charge modulation on the CuO$_2$ unit cell is predominantly of $s$-wave character -- in support of the recent experimental observation.