2021/03/22 by Nei Lopes, Daniel Reyes, M. A. Contínentino +2
Materials Science · Physics and Astronomy · #Charge density #Charge density wave #Condensed matter physics #Coulomb #Density of states #Electron #Electronic band structure #Ground state #Hamiltonian (control theory) #Iron-based superconductors research #Ising model #Lattice (music) #Mean field theory #Phase (matter) #Phase diagram #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Quasiparticle #Rare-earth and actinide compounds #Square lattice #Superconductivity #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.103.195150
published as Phys. Rev. B 103, 195150 (2021) · 11 pages and 10 figures
arxiv created 2021/03/22 · openalex publication_date 2021/05/24 · arxiv updated 2021/06/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In this work we study the competition or coexistence between charge density wave (CDW) and superconductivity (SC) in a two-band model system in a square lattice. One of the bands has a net attractive interaction (Jd) that is responsible for SC. The model includes on-site Coulomb repulsion between quasiparticles in different bands (Udc) and the hybridization (V) between them. We are interested in describing intermetallic systems with a d-band of moderately correlated electrons, for which a mean-field approximation is adequate, coexisting with a large sp-band. For simplicity, all interactions and the hybridization V are considered site-independent. We obtain the eigenvalues of the Hamiltonian numerically and minimize the free energy density with respect to the relevant parameters to obtain the phase diagrams as function of Jd, Udc, V, band-filling (ntot), and the relative depth of the bands (\ensuremathεd0). We consider two types of superconducting ground states coexisting with the CDW. One is a homogeneous ground state and the other is a pair density wave where the SC order parameter has the same spatial modulation of the CDW. Our results show that the CDW and SC orders compete, but depending on the parameters of the model these phases may coexist. The model reproduces most of the experimental features of high dimensionality (d>1) metals with competing CDW and SC states, including the existence of first- and second-order phase transitions in their phase diagrams.