Phase diagram of coupled two-leg Cu-O ladders, a renormalization group perspective

Florian Schütz, Brown University, RI.

Two-leg Hubbard ladders are the simplest possible toy model to study non-trivial electronic ordering in interacting many-electron systems. Due to the availability of controlled analytical and numerical methods in one dimension, their phase diagram has been extensively studied. Experimental realizations are of a quasi one-dimensional nature with weak two-dimensional interladder hopping and interaction terms. In particular, the Ca doped spin-ladder compound Sr₁₄Cu₂₄O_{41 has a complex phase diagram including charge-density-wave order as well as unconventional superconductivity under high doping and high pressure. Using weak coupling renormalization group and bosonization techniques as well as a many-patch functional renormalization group scheme, we study a model of coupled Cu2O5 ladders. We investigate instabilities towards charge, spin, and pairing order as a function of hole doping, inter-ladder hopping, and interaction strength starting from experimentally relevant hopping parameters.}