2004/12/31 by J. O. Fjaerestad, J. O. Fjærestad, J. B. Marston +2
Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Charge (physics) #Charge density #Charge density wave #Condensed matter physics #High-pressure geophysics and materials #Hubbard model #Mathematical physics #Organic and Molecular Conductors Research #Physics #Physics of Superconductivity and Magnetism #Quantum electrodynamics #Quantum mechanics #Superconductivity #cond-mat.str-el
paper · pdf · doi:10.1016/j.aop.2005.08.005
published as Ann. Phys. (N.Y.) 321, 894 (2006) · 24 pages, 17 figures. Follow-up to cond-mat/0209444. (v2) Some revisions in text, improved presentation. Minor changes in title, abstract and references
arxiv created 2005/04/06 · openalex publication_date 2005/11/03 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study a generalized Hubbard model on the two-leg ladder at zero temperature, focusing on a parameter region with staggered flux (SF)/d-density wave (DDW) order. To guide our numerical calculations, we first investigate the location of a SF/DDW phase in the phase diagram of the half-filled weakly interacting ladder using a perturbative renormalization group (RG) and bosonization approach. For hole doping delta away from half-filling, finite-size density-matrix renormalization-group (DMRG) calculations are used to study ladders with up to 200 rungs for intermediate-strength interactions. In the doped SF/DDW phase, the staggered rung current and the rung electron density both show periodic spatial oscillations, with characteristic wavelengths 2/delta and 1/delta, respectively, corresponding to ordering wavevectors 2kF and 4kF for the currents and densities, where 2kF = pi(1-delta). The density minima are located at the anti-phase domain walls of the staggered current. For sufficiently large dopings, SF/DDW order is suppressed. The rung density modulation also exists in neighboring phases where currents decay exponentially. We show that most of the DMRG results can be qualitatively understood from weak-coupling RG/bosonization arguments. However, while these arguments seem to suggest a crossover from non-decaying correlations to power-law decay at a length scale of order 1/delta, the DMRG results are consistent with a true long-range order scenario for the currents and densities.