2020/08/24 by Y. D. Wang, W. L. Yao, Z. M. Xin +6 · 193 citations
Materials Science · Physics and Astronomy · #2D Materials and Applications #Advanced Condensed Matter Physics #Coulomb #Ground state #Insulator (electricity) #Magnetism #Metal–insulator transition #Mott insulator #Mott transition #Organic and Molecular Conductors Research #Photoemission spectroscopy #Stacking #cond-mat.mtrl-sci #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1038/s41467-020-18040-4
published in Nature Communications 11(1), 4215 (Nature Portfolio) · 5 figures, Supplementary information
openalex publication_date 2020/08/24 · arxiv created 2020/08/25 · arxiv updated 2020/08/26 · openalex created_date 2020/09/01 · openalex updated_date 2026/08/05
Abstract 1 T -TaS 2 undergoes successive phase transitions upon cooling and eventually enters an insulating state of mysterious origin. Some consider this state to be a band insulator with interlayer stacking order, yet others attribute it to Mott physics that support a quantum spin liquid state. Here, we determine the electronic and structural properties of 1 T -TaS 2 using angle-resolved photoemission spectroscopy and X-Ray diffraction. At low temperatures, the 2π/2c-periodic band dispersion, along with half-integer-indexed diffraction peaks along the c axis, unambiguously indicates that the ground state of 1 T -TaS 2 is a band insulator with interlayer dimerization. Upon heating, however, the system undergoes a transition into a Mott insulating state, which only exists in a narrow temperature window. Our results refute the idea of searching for quantum magnetism in 1 T -TaS 2 only at low temperatures, and highlight the competition between on-site Coulomb repulsion and interlayer hopping as a crucial aspect for understanding the material’s electronic properties.