2001/03/21 by F. H. L. Essler, Fabian H. L. Eßler, Florian Gebhard +3 · 2 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Biexciton #Binding energy #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Coulomb #Exciton #Hubbard model #Mott insulator #Mott transition #Optical conductivity #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Renormalization #Superconductivity #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.64.125119
published as Phys. Rev. B 64, 125119 (2001) · 15 pages, 6 eps figures, corrected typos in labels of figures 4,5, and 6
arxiv created 2001/03/21 · openalex publication_date 2001/09/11 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We employ dynamical density-matrix renormalization-group (DDMRG) and field-theory methods to determine the frequency-dependent optical conductivity in one-dimensional extended, half-filled Hubbard models. The field-theory approach is applicable to the regime of ``small'' Mott gaps which is the most difficult to access by DDMRG. For very large Mott gaps the DDMRG recovers analytical results obtained previously by means of strong-coupling techniques. We focus on exciton formation at energies below the onset of the absorption continuum. As a consequence of spin-charge separation, these Mott-Hubbard excitons are bound states of spinless, charged excitations (``holon-antiholon'' pairs). We also determine exciton binding energies and sizes. In contrast to simple band insulators, we observe that excitons exist in the Mott-insulating phase only for a sufficiently strong intersite Coulomb repulsion. Furthermore, our results show that the exciton binding energy and size are not related in a simple way to the strength of the Coulomb interaction.