2003/02/28 by E. Orignac, R. Citro · 2 citations
Materials Science · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Organic and Molecular Conductors Research #Physics of Superconductivity and Magnetism #cond-mat.str-el
paper · pdf · doi:10.1140/epjb/e2003-00183-6
published as Eur. Phys. J. B 33 p. 419 (2003) · RevTeX 4, 28 pages, 16 EPS figures (v2: fixed documentclass), (v3: corr. in Sec. VI B 2)
arxiv created 2003/03/15 · openalex publication_date 2003/06/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We investigate the phase diagram of a quarter filled Hubbard ladder with nearest-neighbor Coulomb repulsion using bosonization and renormalization group approach. Focusing on the strong-repulsion regime, we discuss the effect of an interchain exchange interaction J and interchain repulsion V on the possible ground states of the system and charge order configurations. Since the spin excitations always possess a gap, we find competing bond-order wave and charge density wave phases as possible ground states of the ladder model. We discuss the elementary excitations in these various phases and point an analogy between the excitations on some of these phases and those of a Kondo-Heisenberg insulator. We also study the order of the quantum phase transitions between the different ground states of the system. We obtain second order transitions in the Ising or SU(2)2 universality class or first order transitions. We map the complete phase diagram in the J-V plane by integrating perturbative renormalization-group equations. Finally, we discuss the effect of doping away from half-filling and the effect of an applied magnetic field.