A heavy-fermion superconductor UPt3 is a unique spin-triplet superconductor with multiple superconducting phases. Here we provide the first report on the first-principles analysis of the microscopic superconducting gap structure. We find that the promising gap structure is an unprecedented E2u state, which is completely different from the previous phenomenological E2u models. Our obtained E2u state has in-plane twofold vertical line nodes on small Fermi surfaces and point nodes with linear dispersion on a large Fermi surface. These peculiar features cannot be explained in the conventional spin 1/2 representation, but is described by the group-theoretical representation of the Cooper pairs in the total angular momentum j=5/2 space. Our findings shed new light on the long-standing problems in the superconductivity of UPt3
@article{arxiv.1607.02708,
title = {Exotic multi-gap structure in UPt$_3$ unveiled by the first-priniciples analysis},
author = {Takuya Nomoto and Hiroaki Ikeda},
journal= {arXiv preprint arXiv:1607.02708},
year = {2016}
}