2002/08/26 by Eric Jeckelmann · 3 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Band gap #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Density matrix renormalization group #Excited state #Exciton #Hubbard model #Mott insulator #Mott transition #Optical conductivity #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Renormalization group #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.67.075106
published as Phys. Rev. B 67, 075106 (2003) · 12 pages (REVTEX 4), 12 figures (in 14 eps files), 1 table
arxiv created 2002/08/26 · openalex publication_date 2003/02/14 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The density-matrix renormalization-group (DMRG) method is used to investigate optical excitations in the Mott insulating phase of a one-dimensional extended Hubbard model. The linear optical conductivity is calculated using the dynamical DMRG method and the nature of the lowest optically excited states is investigated using a symmetrized DMRG approach. The numerical calculations agree perfectly with field-theoretical predictions for a small Mott gap and analytical results for a large Mott gap obtained with a strong-coupling analysis. It is shown that four types of optical excitations exist in this Mott insulator: pairs of unbound charge excitations, excitons, excitonic strings, and charge-density-wave (CDW) droplets. Each type of excitation dominates the low-energy optical spectrum in some region of the interaction parameter space and corresponds to distinct spectral features: a continuum starting at the Mott gap (unbound charge excitations), a single peak or several isolated peaks below the Mott gap (excitons and excitonic strings, respectively), and a continuum below the Mott gap (CDW droplets).