2007/07/31 by G. Roux, Guillaume Roux, E. Orignac +4 · 6 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.76.195105
published as Phys. Rev. B 76, 195105 (2007) · 15 pages, 17 figures
openalex publication_date 2007/11/02 · arxiv created 2007/11/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the magnetic orbital effect of a doped two-leg ladder in the presence of a magnetic field component perpendicular to the ladder plane. Combining both low-energy approach (bosonization) and numerical simulations (density-matrix renormalization group) on the strong coupling limit (t\text\ensuremath-J model), a rich phase diagram is established as a function of hole doping and magnetic flux. Above a critical flux, the spin gap is destroyed and a Luttinger liquid phase is stabilized. Above a second critical flux, a reentrance of the spin gap at high magnetic flux is found. Interestingly, the phase transitions are associated with a change of sign of the orbital susceptibility. Focusing on the small magnetic field regime, the spin-gapped superconducting phase is robust, but immediately acquires algebraic transverse (i.e., along rungs) current correlations which are commensurate with the 4kF density correlations. In addition, we have computed the zero-field orbital susceptibility for a large range of doping and interaction ratio J∕t: we found strong anomalies at low J∕t only in the vicinity of the commensurate fillings corresponding to \ensuremathδ=1∕4 and 1∕2. Furthermore, the behavior of the orbital susceptibility reveals that the nature of these insulating phases is different: while for \ensuremathδ=1∕4 a 4kF charge density wave is confirmed, the \ensuremathδ=1∕2 phase is shown to be a bond order wave.