title: Probing the superconducting gap symmetry of PrOs4Sb12: a penetration depth study.
abstract: We report measurements of the magnetic penetration depth lambda in single crystals of PrOs4Sb12 down to 0.1 K, with the ac field applied along the a, b, and c directions. In all three field orientations, lambda approximately T2 and superfluid density rho(s) approximately T2 for T<0.3T(c). Data are best fit by the 3He A-phase-like gap with multidomains, each having two point nodes along a cube axis, and parameter Delta(0)(0)/k(B)T(c)=2.6, suggesting that PrOs4Sb12 is a strong-coupling superconductor with two point nodes on the Fermi surface. We also confirm the double transitions at 1.75 and 1.85 K seen in other measurements.
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Street, Urbana, Illinois 61801, USA.
authors.forename: Elbert E M
authors.initials: EE
authors.lastname: Chia
authors.forename: M B
authors.initials: MB
authors.lastname: Salamon
authors.forename: H
authors.initials: H
authors.lastname: Sugawara
authors.forename: H
authors.initials: H
authors.lastname: Sato