Orbital currents and charge density waves in a generalized Hubbard ladder

Journal Article · Sat Apr 15 04:00:00 EDT 2006 · Annals of Physics (New York)

DOI:https://doi.org/10.1016/j.aop.2005.08.005· OSTI ID:20767003

Fjaerestad, J O ^[1]; Marston, J B ^[2]; Schollwoeck, U ^[3]

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1. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States) and Department of Physics, University of Queensland, Brisbane, Qld 4072 (Australia)
2. Department of Physics, Brown University, Providence, RI 02912 (United States)
3. Institute for Theoretical Physics C, RWTH Aachen, D-52056 Aachen (Germany)

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-system 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 2k {sub F} and 4k {sub F} for the currents and densities, where 2k {sub F} = {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.

• OSTI ID: 20767003
• Journal Information: Annals of Physics (New York), Journal Name: Annals of Physics (New York) Journal Issue: 4 Vol. 321; ISSN 0003-4916; ISSN APNYA6
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOSON EXPANSION
CHARGE DENSITY
CORRELATIONS
DENSITY MATRIX
ELECTRON DENSITY
FOCUSING
HOLES
HUBBARD MODEL
INTERACTIONS
MODULATION
OSCILLATIONS
PERIODICITY
PHASE DIAGRAMS
RENORMALIZATION
WAVELENGTHS