期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2018
卷号：115
期号：38
页码：9503-9508
DOI：10.1073/pnas.1801650115
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Topological Weyl semimetals (TWSs) with pairs of Weyl points and topologically protected Fermi arc states have broadened the classification of topological phases and provide superior platform for study of topological superconductivity. Here we report the nontrivial superconductivity and topological features of sulfur-doped Td -phase MoTe2 with enhanced Tc compared with type-II TWS MoTe2. It is found that Td -phase S-doped MoTe2 (MoTe2− x S x , x ∼ 0.2) is a two-band s -wave bulk superconductor (∼0.13 meV and 0.26 meV), where the superconducting behavior can be explained by the s +− pairing model. Further, measurements of the quasi-particle interference (QPI) patterns and a comparison with band-structure calculations reveal the existence of Fermi arcs in MoTe2− x S x . More interestingly, a relatively large superconducting gap (∼1.7 meV) is detected by scanning tunneling spectroscopy on the sample surface, showing a hint of topological nontrivial superconductivity based on the pairing of Fermi arc surface states. Our work demonstrates that the Td -phase MoTe2− x S x is not only a promising topological superconductor candidate but also a unique material for study of s +− superconductivity.
关键词：Td MoTe2− x S x ; Weyl semimetal ; s +− superconductivity ; topological superconductivity
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