Determining the structure of the superconducting gap in Cu_{2}O_{3} 2-leg ladder materials

TL;DR

This paper investigates the superconducting gap structure in Cu_{2}O_{3} 2-leg ladder materials, using phenomenological calculations to guide experimental efforts in identifying the gap's sign change.

Contribution

It provides theoretical estimates for experimental resolution needed to determine the superconducting gap structure in ladder materials.

Findings

Estimates of nuclear relaxation rates for gap detection

Predictions of inelastic neutron scattering signatures

Guidelines for experimental resolution requirements

Abstract

Superconductivity has been recently observed in Sr_{0.4}Ca_{13.6}Cu_{24}O_{41.84} which contains quasi-one-dimensional Cu_{2}O_{3} 2-leg ladders. If, as suggested by some theories, the superconductivity arises from these 2-leg ladders, it will be important to determine the structure of the superconducting gap. In particular, does the gap in a 2-leg ladder change sign when one goes from the bonding to antibonding fermi surface points? Here we carry out phenomenological calculations of nuclear relaxation rates and inelastic neutron scattering intensity in order to provide estimates of the experimental resolution that will be required to determine the structure of the superconducting gap associated with an array of weakly coupled 2-leg ladders.