<p>The discovery of superconductivity in twisted&#xa0;bilayer and trilayer graphene<sup><CitationRef AdditionalCitationIDS="CR2 CR3 CR4" CitationID="CR1">1</CitationRef>–<CitationRef CitationID="CR5">5</CitationRef></sup> has generated tremendous interest. The key feature of these systems is an interplay between interlayer coupling and a moiré superlattice that gives rise to low-energy flat bands with strong correlations<sup><CitationRef CitationID="CR6">6</CitationRef></sup>. Flat bands can also be induced by moiré patterns in lattice-mismatched and/or twisted heterostructures of other two-dimensional materials, such as transition metal dichalcogenides (TMDs)<sup><CitationRef CitationID="CR7">7</CitationRef>,<CitationRef CitationID="CR8">8</CitationRef></sup>. Although a wide range of correlated phenomena have indeed been observed in moiré TMDs<sup><CitationRef AdditionalCitationIDS="CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18" CitationID="CR9">9</CitationRef>–<CitationRef CitationID="CR19">19</CitationRef></sup>, robust demonstration of superconductivity has remained absent<sup><CitationRef CitationID="CR9">9</CitationRef></sup>. Here we report superconductivity in 5.0° twisted&#xa0;bilayer WSe<sub>2</sub> with a maximum critical temperature of 426 mK. The superconducting state appears in a limited region of displacement field and density that is adjacent to a metallic state with a&#xa0;Fermi surface reconstruction believed to arise from AFM order<sup><CitationRef CitationID="CR20">20</CitationRef></sup>. A sharp boundary is observed between the superconducting and magnetic phases at low temperature, reminiscent of spin fluctuation-mediated superconductivity<sup><CitationRef CitationID="CR21">21</CitationRef></sup>. Our results establish that moiré flat-band superconductivity extends beyond graphene structures. Material properties that are absent in graphene but intrinsic among TMDs, such as a native band gap, large spin–orbit coupling, spin-valley locking and magnetism, offer the possibility of accessing a broader superconducting parameter space than graphene-only structures.</p>

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Superconductivity in 5.0° twisted bilayer WSe2

  • Yinjie Guo,
  • Jordan Pack,
  • Joshua Swann,
  • Luke Holtzman,
  • Matthew Cothrine,
  • Kenji Watanabe,
  • Takashi Taniguchi,
  • David G. Mandrus,
  • Katayun Barmak,
  • James Hone,
  • Andrew J. Millis,
  • Abhay Pasupathy,
  • Cory R. Dean

摘要

The discovery of superconductivity in twisted bilayer and trilayer graphene15 has generated tremendous interest. The key feature of these systems is an interplay between interlayer coupling and a moiré superlattice that gives rise to low-energy flat bands with strong correlations6. Flat bands can also be induced by moiré patterns in lattice-mismatched and/or twisted heterostructures of other two-dimensional materials, such as transition metal dichalcogenides (TMDs)7,8. Although a wide range of correlated phenomena have indeed been observed in moiré TMDs919, robust demonstration of superconductivity has remained absent9. Here we report superconductivity in 5.0° twisted bilayer WSe2 with a maximum critical temperature of 426 mK. The superconducting state appears in a limited region of displacement field and density that is adjacent to a metallic state with a Fermi surface reconstruction believed to arise from AFM order20. A sharp boundary is observed between the superconducting and magnetic phases at low temperature, reminiscent of spin fluctuation-mediated superconductivity21. Our results establish that moiré flat-band superconductivity extends beyond graphene structures. Material properties that are absent in graphene but intrinsic among TMDs, such as a native band gap, large spin–orbit coupling, spin-valley locking and magnetism, offer the possibility of accessing a broader superconducting parameter space than graphene-only structures.