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Weak-coupling phase diagrams of bond-aligned and diagonal doped Hubbard ladders

Shirit Baruch·Dror Orgad
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Abstract

We study, using a perturbative renormalization group technique, the phase diagrams of bond-aligned and diagonal Hubbard ladders defined as sections of a square lattice with nearest-neighbor and next-nearest-neighbor hopping. We find that for not too large hole doping and small next-nearest-neighbor hopping the bond-aligned systems exhibit a fully spin-gapped phase while the diagonal systems remain gapless. Increasing the next-nearest-neighbor hopping typically leads to a decrease of the gap in the bond-aligned ladders, and to a transition into a gapped phase in the diagonal ladders. Embedding the ladders in an antiferromagnetic environment can lead to a reduction in the extent of the gapped phases. These findings suggest a relation between the orientation of hole-rich stripes and superconductivity as observed in LSCO.

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Shirit Baruch, Dror Orgad. 2005-07-27. Weak-coupling phase diagrams of bond-aligned and diagonal doped Hubbard ladders. https://doi.org/10.1103/physrevb.71.184503

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