Yasumasa Tsutsumi, Kazushige Machida, Tetsuo Ohmi, Masa-aki Ozaki
Motivated by recent angle-resolved thermal conductivity experiment that shows
twofold gap symmetry in the high field and low temperature C phase in a heavy
fermion superconductor UPt$_3$, we group-theoretically identify the pairing
functions as $E_{1u}$ with the f-wave character for all three phases. Those are
consistent with this observation in addition to variety of existing
measurements. By using microscopic quasi-classical Eilenberger equation with
this identified triplet pairing function under applied fields, we develop
detailed studies of the vortex structures for three phases, including the
vortex lattice symmetry, local density of states, and the internal field
distribution. These quantities are directly measurable experimentally via SANS,
STM/STS, and NMR, respectively. It is found that in the B phase of low H and
low T the double-core vortex is stabilized over the singular vortex. For the C
phase thermal conductivity data are analyzed to confirm the gap structure
proposed. We also give detailed comparisons of various proposed pair functions,
concluding that the present $E_{1u}$ with f-wave, which is analogue to the
triplet planar state, is better than $E_{2u}$ or $E_{1g}$ scenarios. Finally we
touch upon the surface topological aspects of Majorana modes associated with
the $E_{1u}^f$ state of the planar like features.
View original:
http://arxiv.org/abs/1202.1894
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