2017/04/18 by Z. Guguchia, F. v. Rohr, Z. Shermadini +17 · 1 citation
Physics and Astronomy · #cond-mat.supr-con #cond-mat.mtrl-sci #cond-mat.other
paper · pdf · doi:10.1038/s41467-017-01066-6
published as Nature Communications 8, 1082 (2017) · 15 pages and 9 figures
arxiv created 2017/04/18 · arxiv updated 2018/08/29
MoTe2, with the orthorhombic Td phase, is a new type (type-II) of Weyl semimetal, where the Weyl Fermions emerge at the boundary between electron and hole pockets. Non-saturating magnetoresistance (MR), and superconductivity were also observed in Td-MoTe2. Understanding the superconductivity in Td-MoTe2, which was proposed to be topologically non-trivial, is of eminent interest. Here, we report high-pressure (pmax = 1.3 GPa) muon spin rotation experiments on the temperature-dependent magnetic penetration depth in Td-MoTe2. A substantial increase of the superfluid density ns/m^* and a linear scaling with Tc is observed under pressure. Moreover, the superconducting order parameter in Td-MoTe2 is determined to be two gap (s+s)-wave symmetric. We also excluded time reversal symmetry breaking in the SC state with sensitive zero-field μSR experiments. Considering the previous report \citeBalicas1 on the strong suppression of Tc in Td-MoTe2 by disorder, we suggest that s+- (topological order parameter) state is more likely to be realized in MoTe2 than the s++ (trivial) state. Should s+- be the SC gap symmetry, the Td-MoTe2 is, to our knowledge, the first known example of a time reversal invariant topological (Weyl) superconductor.