title: Interplay of Site and Bond Electron-Phonon Coupling in One Dimension.
abstract: The interplay of bond and charge correlations is studied in a one-dimensional model with both Holstein and Su-Schrieffer-Heeger (SSH) couplings to quantum phonons. The problem is solved exactly by quantum Monte Carlo simulations. If one of the couplings dominates, the ground state is a Peierls insulator with long-range bond or charge order. At weak coupling, the results suggest a spin-gapped and repulsive metallic phase arising from the competing order parameters and lattice fluctuations. Such a phase is absent from the pure SSH model even for quantum phonons. At strong coupling, evidence for a continuous transition between the two Peierls states is presented.
authors.affiliation: Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Hohenadler