2003/12/31 by Winfried Koller, W. Koller, D. Meyer +3
Materials Science · Physics and Astronomy · #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1209/epl/i2003-10228-6
published as Europhys. Lett., 66 (4), pp. 559-564 (2004) · 6 pages, 5 figures
arxiv created 2004/02/10 · openalex publication_date 2004/05/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We investigate metal-insulator transitions in the half-filled Holstein-Hubbard model as a function of the on-site electron-electron interaction U and the electron-phonon coupling g . We use several different numerical methods to calculate the phase diagram, the results of which are in excellent agreement. When the electron-electron interaction U is dominant, the transition is to a Mott insulator; when the electron-phonon interaction dominates, the transition is to a localized bipolaronic state. In the former case, the transition is always found to be second order. This is in contrast to the transition to the bipolaronic state, which is clearly first order for larger values of U . We also present results for the quasiparticle weight and the double occupancy as functions of U and g .