Interaction versus dimerization in one - dimensional Fermi systemsCosima

the date of receipt and acceptance should be inserted later Dedicated to J. Zittartz on the occasion of his 60th birthday Abstract. In order to study the eeect of interaction and lattice distortion on quantum coherence in one-dimensional Fermi systems, we calculate the ground state energy and the phase sensitivity of a ring of interacting spinless fermions on a dimerized lattice. Our numerical DMRG studies, in which we keep up to 1000 states for systems of about 100 sites, are supplemented by analytical considerations using bosonization techniques. We nd a delocalized phase for an attractive interaction, which diiers from that obtained for random lattice distortions. The extension of this delocalized phase depends strongly on the dimerization induced modiication of the interaction. Taking into account the harmonic lattice energy, we nd a dimerized ground state for a repulsive interaction only. The dimerization is suppressed at half lling, when the correlation gap becomes large.