Emergent charge order from correlated electron-phonon physics in cuprates

S Banerjee,A P Kampf,W A Atkinson

doi:10.1038/s42005-020-00430-1

S Banerjee, A P Kampf + Show 1 more

Open Access

https://doi.org/10.1038/s42005-020-00430-1

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Journal: Communications Physics	Publication Date: Sep 18, 2020
Citations: 17	License type: open-access

Affiliation: University of Augsburg, Trent University

Abstract

Charge-density wave order is now understood to be a widespread feature of underdoped cuprate high-temperature superconductors, although its origins remain unclear. While experiments suggest that the charge-ordering wavevector is determined by Fermi-surface nesting, the relevant sections of the Fermi surface are featureless and provide no clue as to the underlying mechanism. Here, focusing on underdoped YBa2Cu3O6+x, we propose that charge-density waves form from the incipient softening of a bond-buckling phonon. The momentum dependence of its coupling to itinerant electrons favourably selects the wavevector found in experiments. But, it requires quasiparticle renormalization by strong electronic correlations to enable a unique enhancement of the charge susceptibility near the B1g-phonon selected wavevector. The B1g phonon frequency softens by a few percent, and finite-range charge-density wave correlations will form locally, if nucleated by defects or dopant disorder. These results suggest that underdoped cuprates cannot be understood in the context of strong electronic correlations alone.

Highlights

Charge-density wave order is understood to be a widespread feature of underdoped cuprate high-temperature superconductors, its origins remain unclear
The discovery of charge–density wave (CDW) order[1] in underdoped cuprates raised the question of whether it is intimately related to pseudogap physics[2,3,4,5,6,7], and thereby yet another signature of strong electronic correlations
The CDW wavevector qCO continuously drops with increasing hole doping in YBa2Cu3O6+x (YBCO) and Bi2Sr2−xLaxCuO6+x (Bi-2201)[1,11,16,17], whereas the completely opposite trend is observed in charge-stripe ordered La-based 214 cuprates such as La2−xSrxCuO4 (LSCO) and La2−xBaxCuO4 (LBCO)[18]

Summary

Introduction

Charge-density wave order is understood to be a widespread feature of underdoped cuprate high-temperature superconductors, its origins remain unclear. This leads us to propose a scenario, in which a phonon-based mechanism is enabled by strong electronic correlations, and the incommensurate wavevector of the concomitant charge correlations is dictated by the momentum–space structure of the el–ph coupling matrix element.

Results

Conclusion