Charge order in the pseudogap phase of cuprate superconductors

Abstract

Charge ordering instabilities are studied in a multiorbital model of cuprate superconductors. A known, key feature of thismodel is that the large local Coulomb interaction in the Cudx2-y2 orbitals generates local moments with short range antiferromagnetic (AF) correlations. The strong simplifying ansatz that these moments are static and ordered allows us to explore a regime not generally accessible to weak-coupling approaches. The AF correlations lead to a pseudogap-like reconstruction of the Fermi surface.Wefind that the leading charge instability within this pseudogap-like state is to a phase with a spatially modulated transfer of charge between neighbouring oxygen px and py orbitals accompanied byweakmodulations of the charge density on the Cudx2-y2 orbitals. As a prime result of theAF Fermi-surface reconstruction, the wavevectors of the charge modulations are oriented along the crystalline axes with a periodicity that agrees quantitatively with experiments. This suggests a resolution to a discrepancy between experiments, which find axial order, and previous theoretical calculations, which find modulation wavevectors along the Brillouin zone diagonal. The axial order is stabilized by hopping processes via the Cu4s orbital, which is commonly not included in model analyses of cuprate superconductors. The main implication of our results is that charge order emerges from the pseudogap state, and is not the primary source of the pseudogap.