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TT: Fachverband Tiefe Temperaturen

TT 71: Correlated Electrons: Other Theoretical Topics

TT 71.4: Vortrag

Freitag, 20. März 2020, 10:15–10:30, HSZ 304

Ground-state properties and enhancement of pairing correlations in an asymmetric Hubbard ladder — •Anas Abdelwahab and Eric Jeckelmann — Leibniz Universität Hannover, Hannover, Germany

We investigate ground-state properties and correlation functions of an asymmetric two-leg Hubbard ladder using the density matrix renormalization group method. The ladder consists in a Hubbard chain (Hubbard leg) and a tight-binding chain (Fermi leg) connected by a single-particle hopping between the adjacent sites. This two-leg ladder system is a generalization of the asymmetric ladder investigated in [1,2] by allowing the hopping terms in the Hubbard leg and the Fermi leg to be unequal. We determine the excitation gaps and the corresponding charge and spin densities as well as several correlation functions. For strong on-site interactions at half filling, we observe finite pair-binding energies for range of intra-leg hopping terms in the Hubbard leg and rung hopping terms larger than the intra-leg hopping term in the Fermi leg. There is no enhancement of pairing correlations at half filling. For dopped ladders, the pair-binding energies reduce but persist and we observe strong enhancement of pairing correlations that decay in power-law. The exponent of the dcay is close to one for some parameter sets.

[1] A. Abdelwahab, E. Jeckelmann, M. Hohenadler, Phys. Rev. B 91, 155119 (2015)

[2] A. Abdelwahab, E. Jeckelmann, Eur. Phys. J. B 91, 207 (2018)