2000 character limit reached
Phonon Self-Energy Effects in Migdal-Eliashberg Theory (2101.12084v1)
Published 28 Jan 2021 in cond-mat.supr-con
Abstract: Recent work on an electron-phonon model in two-dimensions is reviewed and some new results are presented. We utilize both Quantum Monte Carlo simulations and Migdal-Eliashberg theory. The type of electron-ion coupling considered is on-site. Competing instabilities are charge density wave (CDW) and singlet superconductivity. When the electron band is half-filled, the charge density wave dominates. Away from half-filling CDW correlations actually suppress superconductivity.