Tomonaga-Luttinger parameters for doped Mott insulatorsS. Ejima1, F. Gebhard1 and S. Nishimoto2
1 Fachbereich Physik, Philipps-Universität Marburg - D-35032 Marburg, Germany
2 Institut für Theoretische Physik, Universität Göttingen D-37077 Göttingen, Germany
received 28 February 2005; accepted in final form 31 March 2005
published online 15 April 2005
The Tomonaga-Luttinger parameter determines the critical behavior in quasi-one-dimensional correlated electron systems, e.g., the exponent for the density of states near the Fermi energy. We use the numerical density-matrix renormalization group method to calculate from the slope of the density-density correlation function in momentum space at zero wave vector. We check the accuracy of our new approach against exact results for the Hubbard and XXZ Heisenberg models. We determine in the phase diagram of the extended Hubbard model at quarter filling, , and confirm the bosonization results on the critical line and at infinitesimal doping of the charge-density-wave (CDW) insulator for all interaction strengths. The doped CDW insulator exhibits exponents only for small doping and strong correlations.
71.10.Fd - Lattice fermion models (Hubbard model, etc.).
71.30.+h - Metal-insulator transitions and other electronic transitions.
71.10.Hf - Non-Fermi-liquid ground states, electron phase diagrams and phase transitions in model systems.
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