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

Fu Zhang, Wenkai Zheng, Yanfu Lu, Lavish Pabbi, Kazunori Fujisawa, Ana Laura Elías, Anna R. Binion, Tomotaroh Granzier-Nakajima, Tianyi Zhang, Yu Lei, Zhong Lin, Eric W. Hudson, Susan B. Sinnott, Luis Balicas, Mauricio Terrones

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish (US)
Pages (from-to)19685-19693
Number of pages9
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number33
DOIs
StatePublished - Aug 2020

All Science Journal Classification (ASJC) codes

  • General

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