2005/05/31 by Takami Tohyama, T. Tohyama, Y. Inoue +5
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.72.045113
published as Phys. Rev. B 72, 045113 (2005) (5 pages) · 5 pages, 5 figures
openalex publication_date 2005/07/11 · arxiv created 2005/07/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The optical conductivity \ensuremathσ(\ensuremathω) in the two-dimensional Hubbard model is examined by applying the exact diagonalization technique to small square clusters with periodic boundary conditions up to √(20)\ifmmode×\else\texttimes\fi√(20) sites. Spectral-weight distributions at half-filling and their doping dependence in the 20-site cluster are found to be similar to those in a √(18)\ifmmode×\else\texttimes\fi√(18) cluster, but different from 4\ifmmode×\else\texttimes\fi4 results. The results for the 20-site cluster enable us to perform a systematic study of the doping dependence of the spectral-weight transfer from the region of the Mott-gap excitation to lower-energy regions. We discuss the dependence of the Drude weight and the effective carrier number on the electron density at a large on-site Coulomb interaction.