Europhys. Lett.
Volume 76, Number 4, November 2006
Page(s) 644 - 650
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 18 October 2006
Europhys. Lett., 76 (4), pp. 644-650 (2006)
DOI: 10.1209/epl/i2006-10327-x

Dominant particle-hole contributions to the phonon dynamics in the spinless one-dimensional Holstein model

S. Sykora1, A. Hübsch2 and K. W. Becker1

1  Institut für Theoretische Physik, Technische Universität Dresden 01062 Dresden, Germany
2  Max-Planck-Institut für Physik komplexer Systeme - Nöthnitzer Straße 38 01187 Dresden, Germany

received 26 May 2006; accepted in final form 27 September 2006
published online 18 October 2006

In the spinless Holstein model at half-filling the coupling of electrons to phonons is responsible for a phase transition from a metallic state at small coupling to a Peierls distorted insulated state when the electron-phonon coupling exceeds a critical value. For the adiabatic case of small phonon frequencies, the transition is accompanied by a phonon softening at the Brillouin-zone boundary whereas a hardening of the phonon mode occurs in the anti-adiabatic case. The phonon dynamics studied in this letter do not only reveal the expected renormalization of the phonon modes but also show remarkable additional contributions due to electronic particle-hole excitations.

71.10.Fd - Lattice fermion models (Hubbard model, etc.).
71.30.+h - Metal-insulator transitions and other electronic transitions.

© EDP Sciences 2006