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Superconductivity enhancement in phase-engineered molybdenum carbide/disulfide vertical heterostructures

Journal Article · · Proceedings of the National Academy of Sciences of the United States of America
 [1];  [2];  [3];  [3];  [4];  [3];  [3];  [3];  [3];  [3];  [3];  [3];  [3];  [5];  [3]
  1. Pennsylvania State Univ., University Park, PA (United States); Penn State, State College, PA (United States), Department of Physics
  2. Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab); Pennsylvania State Univ., University Park, PA (United States)
  3. Pennsylvania State Univ., University Park, PA (United States)
  4. Pennsylvania State Univ., University Park, PA (United States); Shinshu Univ., Wakasato, Nagano (Japan)
  5. Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab)
Stacking layers of atomically thin transition-metal carbides and two-dimensional (2D) semiconducting transition-metal dichalcogenides, could lead to nontrivial superconductivity and other unprecedented phenomena yet to be studied. In this work, superconducting α-phase thin molybdenum carbide flakes were first synthesized, and a subsequent sulfurization treatment induced the formation of vertical heterolayer systems consisting of different phases of molybdenum carbide—ranging from α to γ' and γ phases—in conjunction with molybdenum sulfide layers. These transition-metal carbide/disulfide heterostructures exhibited critical superconducting temperatures as high as 6 K, higher than that of the starting single-phased α-Mo2C (4 K). We analyzed possible interface configurations to explain the observed moiré patterns resulting from the vertical heterostacks. Our density-functional theory (DFT) calculations indicate that epitaxial strain and moiré patterns lead to a higher interfacial density of states, which favors superconductivity. Such engineered heterostructures might allow the coupling of superconductivity to the topologically nontrivial surface states featured by transition-metal carbide phases composing these heterostructures potentially leading to unconventional superconductivity. Moreover, we envisage that our approach could also be generalized to other metal carbide and nitride systems that could exhibit high-temperature superconductivity.
Research Organization:
Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Organization:
National Science Foundation (NSF); USDOE Office of Science (SC)
Grant/Contract Number:
SC0018025
OSTI ID:
1657274
Journal Information:
Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 33 Vol. 117; ISSN 0027-8424
Publisher:
National Academy of SciencesCopyright Statement
Country of Publication:
United States
Language:
English

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