Nontrivial superconductivity in topological MoTe<sub>2-<i>x</i></sub> S <sub><i>x</i></sub> crystals.
basic_science · Level V
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- Record sourced from PubMed, PMID 30166451.
- Also identified by DOI 10.1073/pnas.1801650115 and PMC identifier 6156667.
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Abstract
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 <i>T<sub>d</sub></i> -phase MoTe<sub>2</sub> with enhanced T<sub>c</sub> compared with type-II TWS MoTe<sub>2</sub> It is found that <i>T<sub>d</sub></i> -phase S-doped MoTe<sub>2</sub> (MoTe<sub>2-<i>x</i></sub> S <sub><i>x</i></sub> , <i>x</i> ∼ 0.2) is a two-band <i>s</i>-wave bulk superconductor (∼0.13 meV and 0.26 meV), where the superconducting behavior can be explained by the <i>s</i><sub><i>+-</i></sub> 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 MoTe<sub>2-<i>x</i></sub> S <sub><i>x</i></sub> 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 <i>T<sub>d</sub></i> -phase MoTe<sub>2-<i>x</i></sub> S <sub><i>x</i></sub> is not only a promising topological superconductor candidate but also a unique material for study of <i>s</i><sub><i>+-</i></sub> superconductivity.