1998/12/22 by Chunli Zhang, Eric Jeckelmann, Steven R. White · 1 citation
Computer Science · Mathematics · Physics and Astronomy · #Mathematics #Nonlinear Dynamics and Pattern Formation #Physics #Physics of Superconductivity and Magnetism #Quantum chaos and dynamical systems #Statistical physics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.60.14092
14 pages, 11 eps figures
arxiv created 1998/12/22 · openalex publication_date 1999/11/15 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The spectral weight functions and the optical conductivity of the Holstein model are studied on a one-dimensional six-site lattice with periodic boundary conditions for three different electron concentrations: a single electron, two electrons of opposite spins, and half filling. A density matrix approach is used to obtain an optimal phonon basis and to truncate the phonon Hilbert space without significant loss of accuracy. This approach allows us to calculate spectral functions for electrons dressed locally by the optimal phonons as well as for bare electrons. We obtain evidence for a smooth crossover from quasifree electrons to a heavy itinerant small polaron (single-electron case) or bipolaron (two-electron case) as the electron-phonon coupling strength increases. At half filling, we observe a crossover from a quasifree-electron ground state to a quasidegenerate Peierls charge-density-wave ground state for a finite electron-phonon coupling. This crossover is marked by an abrupt drop of the Drude weight, which is vanishingly small in the Peierls phase.