Journal article

Phases and phase transitions in the half-filled t-t' Hubbard chain

  • Japaridze, Giorgi I. Andronikashvili Institute of Physics, Tbilisi, Georgia
  • Noack, R. M. Fachbereich Physik, Philipps-Universität Marburg, Germany
  • Baeriswyl, Dionys Département de Physique, Université de Fribourg, Switzerland
  • Tincani, L. Fachbereich Physik, Philipps-Universität Marburg, Germany
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  • Physical Review B. - 2007, vol. 76, no. 11, p. 115118
English We study the quantum phase transition from an insulator to a metal realized at t =tc <0.5t in the ground state of the half-filled Hubbard chain with both nearest-neighbor (t) and next-nearest-neighbor (t') hopping. The study is carried out using the bosonization approach and density-matrix renormalization-group calculations. An effective low-energy Hamiltonian that describes the insulator-metal transition is derived. We find that the gross features of the phase diagram are well described by the standard theory of commensurate-incommensurate transitions in a wide range of parameters. We also obtain an analytical expression for the insulator-metal transition line tc (U,t). We present results of density-matrix-renormalization-group calculations of spin and charge distribution in various sectors of the phase diagram. The numerical results support the picture derived from the effective theory and give evidence for the complete separation of the transitions involving spin and charge degrees of freedom.
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