Abstract
We theoretically consider the superconductivity of the topological half-Heusler semimetals YPtBi and LuPtBi. We show that pairing occurs between fermion states, which leads to qualitative differences from the conventional theory of pairing between states. In particular, this permits Cooper pairs with quintet or septet total angular momentum, in addition to the usual singlet and triplet states. Purely on-site interactions can generate -wave quintet time-reversal symmetry-breaking states with topologically nontrivial point or line nodes. These local -wave quintet pairs reveal themselves as -wave states in momentum space. Furthermore, due to the broken inversion symmetry in these materials, the -wave singlet state can mix with a -wave septet state, again with topologically stable line nodes. Our analysis lays the foundation for understanding the unconventional superconductivity of the half-Heuslers.
- Received 5 November 2015
DOI:https://doi.org/10.1103/PhysRevLett.116.177001
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