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arXiv · 1502.06050

$d$-wave superconductivity in coupled ladders

J. P. L. Faye·S. R. Hassan·P. V. Sriluckshmy·G. Baskaran·D. Sénéchal
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Abstract

We study the one-band Hubbard model on the trellis lattice, a two-dimensional frustrated lattice of coupled two-leg ladders, with hopping amplitude $t$ within ladders and $t'$ between ladders. For large $U/t$ this is a model for the cuprate Sr$_{14-x}$Ca$_x$Cu$_{24}$O$_{41}$. We investigate the phase diagram as a function of doping for $U=10t$ using two quantum cluster methods: The variational cluster approximation (VCA), with clusters of sizes 8 and 12, and Cellular dynamical mean field theory (CDMFT), both at zero temperature. Both methods predict a superconducting dome, ending at roughly 20\% doping in VCA and 15\% in CDMFT. In VCA, the superconducting order parameter is complex in a range of doping centered around 10\%, corresponding to bulk chiral, $T$-violating superconductivity. However, the CDMFT solution is not chiral. We find evidence for a migration of the Cooper pairs from the inter-ladder region towards the plaquettes as doping is increased.

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J. P. L. Faye, S. R. Hassan, P. V. Sriluckshmy, G. Baskaran, D. Sénéchal. 2015-02-21. $d$-wave superconductivity in coupled ladders. https://doi.org/10.1103/physrevb.91.195126

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