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Inhomogeneously doped two-leg ladder systems

Stefan Wessel·Martin Indergand·Andreas Laeuchli·Urs Ledermann·Manfred Sigrist
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Abstract

A chemical potential difference between the legs of a two-leg ladder is found to be harmful for Cooper pairing. The instability of superconductivity in such systems is analyzed by compairing results of various analytical and numerical methods. Within a strong coupling approach for the t-J model, supplemented by exact numerical diagonalization, hole binding is found unstable beyond a finite, critical chemical potential difference. The spinon-holon mean field theory for the t-J model shows a clear reduction of the the BCS gaps upon increasing the chemical potential difference leading to a breakdown of superconductivity. Based on a renormalization group approach and Abelian bosonization, the doping dependent phase diagram for the weakly interacting Hubbard model with different chemical potentials was determined.

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Stefan Wessel, Martin Indergand, Andreas Laeuchli, Urs Ledermann, Manfred Sigrist. 2003-04-11. Inhomogeneously doped two-leg ladder systems. https://doi.org/10.1103/physrevb.67.184517

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