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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons - Poster Session

TT 20.81: Poster

Wednesday, March 28, 2007, 14:00–17:45, Poster A

Phonon simulations with arbitrary dispersions — •Hans Gerd Evertz, Franz Michel, and Peter Pippan — Theoretical and Computational Physics, TU Graz, 8010 Graz, Austria

We describe a new Quantum Monte Carlo method that allows the efficient simulation of phonons with arbitrary bare dispersion, coupled to spins in any dimension, or to 1d electrons.

We examine the spin Peierls transition in 1d in the case of optical phonons and of acoustical phonons and show that it occurs at the same coupling. Detailed phonon spectra exhibit both a central peak and softening, depending on the bare phonon frequency at momentum π. In 2d we examine the stripe pattern of coupled chains. We contrast the behavior of spin-phonon systems to that of coupled electrons and phonons.