Room Temperature Commensurate Charge Density Wave on Epitaxially Grown Bilayer 2H-Tantalum Sulfide on Hexagonal Boron Nitride

Wei Fu, Jingsi Qiao, Xiaoxu Zhao, Yu Chen, Deyi Fu, Wei Yu, Kai Leng, Peng Song, Zhi Chen, Ting Yu, Stephen J. Pennycook, Su Ying Quek, Kian Ping Loh

Research output: Journal article publicationJournal articleAcademic researchpeer-review

17 Citations (Scopus)


The breaking of multiple symmetries by periodic lattice distortion at a commensurate charge density wave (CDW) state is expected to give rise to intriguing interesting properties. However, accessing the commensurate CDW state on bulk TaS2 crystals typically requires cryogenic temperatures (77 K), which precludes practical applications. Here, we found that heteroepitaxial growth of a 2H-tantalum disulfide bilayer on a hexagonal-boron nitride (h-BN) substrate produces a robust commensurate CDW order at room temperature, characterized by a Moiré superlattice of 3 × 3 TaS2 on a 4 × 4 h-BN unit cell. The CDW order is confirmed by scanning transmission electron microscopy and Raman measurements. Theoretical calculations reveal that the stabilizing energy for the CDW phase of the monolayer and bilayer 2H-TaS2-on-h-BN substrates arises primarily from interfacial electrostatic interactions and, to a lesser extent, interfacial strain. Our work shows that engineering interfacial electrostatic interactions in an ultrathin van der Waals heterostructure constitutes an effective way to enhance CDW order in two-dimensional materials.

Original languageEnglish
JournalACS Nano
Publication statusAccepted/In press - 28 Apr 2020
Externally publishedYes


  • charge density wave
  • interfacial electrostatic interaction
  • Moiré superlattice
  • molecular beam epitaxy
  • two-dimensional transition metal dichalcogenides

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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