Intrinsic Pair Density Waves in CDMFT Improve Agreement with Cuprates

Cluster dynamical mean-field theory (CDMFT) is one of the most successful methods to treat strongly correlated electrons systems. It is well known, however, that CDMFT leads to an artificial breaking of translational invariance. Here, we investigate how this manifests itself. We report artificial density waves taking the shape of the cluster (cluster density waves) in all our CDMFT solutions. In particular, we report pair density waves in the superconducting solution. We discuss how these artificial density waves help the agreement of CDMFT with the low-energy spectra of cuprate high temperature superconductors. Namely, we find subgap structures similar to those found in tunnelling experiments and a related separation between nodal and anti-nodal gaps in the spectral weight, as observed in photoemission experiments. This agreement with cuprates suggests that spatial inhomogeneity is an important ingredient to explain the low-energy spectrum of cuprates, even in the strongly correlated case.