1995/08/31 by H. Endres, R. M. Noack, W. Hanke +3 · 1 citation
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #cond-mat
paper · pdf · doi:10.1103/physrevb.53.5530
published as Phys. Rev. B 53 (1996) 5530 · 9 pages + 10 postscript figures, submitted to Phys.Rev.B, revised version with isotropic t_perp=t data included
arxiv created 1995/11/20 · openalex publication_date 1996/03/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Using grand canonical quantum Monte Carlo (QMC) simulations combined with maximum entropy analytic continuation, as well as analytical methods, we examine the one- and two-particle dynamical properties of the Hubbard model on two coupled chains at half-filling. The one-particle spectral weight function, A(k,\ensuremathω), undergoes a qualitative change with interchain hopping t_\mathrm\ensuremath⊥ associated with a transition from a four-band insulator to a two-band insulator. A simple analytical model based on the propagation of exact rung singlet states gives a good description of the features at large t_\mathrm\ensuremath⊥. For smaller t_\mathrm\ensuremath⊥, A(k,\ensuremathω) is similar to that of the one-dimensional model, with a coherent band of width the effective antiferromagnetic exchange J which is reasonably well described by renormalized spin-wave theory. The coherent band rides on a broad background of width several times the parallel hopping integral t, an incoherent structure similar to that found in calculations on both the one- and two-dimensional models. We also present QMC results for the two-particle spin and charge excitation spectra, and relate their behavior to the rung singlet picture for large t_\mathrm\ensuremath⊥ and to the results of spin-wave theory for small t_\mathrm\ensuremath⊥. \textcopyright 1996 The American Physical Society.