Charge order with unusual star-of-David lattice in monolayer NbTe2

Taiki Taguchi, Katsuaki Sugawara, Hirofumi Oka, Tappei Kawakami, Yasuaki Saruta, Takemi Kato, Kosuke Nakayama, Seigo Souma, Takashi Takahashi, Tomoteru Fukumura, Takafumi Sato

研究成果: Article査読

1 被引用数 (Scopus)


Interplay between fermiology and electron correlation is crucial for realizing exotic quantum phases. Transition-metal dichalcogenide (TMD) 1T-TaS2 has sparked tremendous attention owing to its unique Mott-insulating phase coexisting with the charge-density wave (CDW). However, how the fermiology and electron correlation are associated with such properties has yet to be clarified. Here we demonstrate that monolayer 1T-NbTe2 is a new class of two-dimensional TMD which has the star-of-David lattice similarly to bulk TaS2 and isostructural monolayer NbSe2, but exhibits a metallic ground state with an unusual lattice periodicity (19×19) characterized by the sparsely occupied star-of-David lattice. By using angle-resolved photoemission and scanning-tunneling spectroscopies in combination with first-principles band-structure calculations, we found that the hidden Fermi-surface nesting and associated CDW formation are a primary cause to realize this unique correlated metallic state with no signature of Mott gap. The present result points to a vital role of underlying fermiology to characterize the Mott phase of TMDs.

ジャーナルPhysical Review B
出版ステータスPublished - 2023 1月 15

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学


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