Nontrivial superconductivity signatures in topological MoTe<sub>2</sub><sub>−x</sub>S<sub>x</sub> crystals
ORAL
Abstract
Topological Weyl semimetals (TWSs) and topological Dirac semimetals have broadened the classification of topological phases and provide new platforms for studying topological superconductivity. Here, we report a systematic study of superconductivity in sulfur-doped Td-phase MoTe2 with enhanced Tc compared with type-II TWS MoTe2. We found that Td-phase S-doped MoTe2 (MoTe2−xSx, x ∼ 0.2) is a two-band s-wave bulk superconductor (superconducting gap∼0.13 meV and 0.26 meV), where the superconducting behavior can be explained by the s+− pairing model. We also used scanning tunneling spectroscopy to detect a relatively large surface superconducting gap (∼1.7 meV), suggestive of topologically nontrivial superconductivity based on the pairing of Fermi arc surface states. Indeed, a comparison of the quasi-particle interference patterns with band-structure calculations indicates Fermi arcs in MoTe2−xSx. Our results demonstrates that the Td-phase MoTe2−xSx might be a promising topological superconductor candidate and also a unique material for studying s+− superconductivity.
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Presenters
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Yanan Li
- Department of Physics and Materials Research Institute, Pennsylvania State University
- Pennsylvania State University