The anisotropy of the London penetration depth is evaluated for two-band superconductors with arbitrary inter- and intra-band scattering times. If one of the bands is clean and the other is dirty in the absence of inter-band scattering, the anisotropy is dominated by the Fermi surface of the clean band and is weakly temperature dependent. The inter-band scattering also suppress the temperature dependence of the anisotropy.
@article{arxiv.cond-mat/0311331,
title = {Penetration depth anisotropy in two-band superconductors},
author = {V. G. Kogan and N. V. Zhelezina},
journal= {arXiv preprint arXiv:cond-mat/0311331},
year = {2009}
}