2023/01/01 by Nicklas Enenkel, Enenkel, Nicklas, Markus Garst +3 · 1 citation
Chemistry · Physics and Astronomy · #FOS: Physical sciences #Inorganic Fluorides and Related Compounds #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #Surface and Thin Film Phenomena
paper · pdf · doi:10.48550/arxiv.2309.14035
openalex publication_date 2023/01/01 · openalex created_date 2023/09/27 · openalex updated_date 2026/07/28
We present important use cases and limitations when considering results obtained from cluster perturbation theory (CPT). CPT combines the solutions of small individual clusters of an infinite lattice system with the Bloch theory of conventional band theory to provide an approximation for the Green’s function in the thermodynamic limit. To this end, we are investigating single-band and multi-band Hubbard models in 1D and 2D systems. A special interest is taken in the supposed pseudogap regime of the 2D square lattice at half-filling and intermediate interaction strength (U≤3t) as well as the metal–insulator transition. We point out that the finite-size level spacing of the cluster limits the resolution of spectral features within CPT. This restricts the investigation of asymptotic properties of the metal–insulator transition, as it would require much larger cluster sizes that are beyond computational capabilities.