Pressure-induced metallic state in a van der Waals cluster Mott insulator Nb3Cl8

Article Chemistry, Physical

A symmetry-orientated divide-and-conquer method for crystal structure prediction

Xuecheng Shao et al.

Summary: This study proposes a symmetry-orientated divide-and-conquer scheme to simplify the problem of crystal structure prediction, and successfully predicts candidate structures of complex systems.

JOURNAL OF CHEMICAL PHYSICS (2022)

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Article Chemistry, Multidisciplinary

Observation of Topological Flat Bands in the Kagome Semiconductor Nb3Cl8

Zhenyu Sun et al.

Summary: The presence of a breathing kagome lattice in Nb3Cl8 leads to a band gap, but the topological flat bands (TFBs) are preserved. Through experimental observation and computational analysis, we confirm the existence of TFBs and a moderate band gap in Nb3Cl8. Mechanical exfoliation successfully yields stable monolayer Nb3Cl8 under ambient conditions. Additionally, calculations reveal a magnetic ground state in monolayer Nb3Cl8, offering opportunities to study the interplay between geometry, topology, and magnetism.

NANO LETTERS (2022)

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Article Physics, Multidisciplinary

Pressure-driven symmetry breaking and electron disproportionation of the trigonal Nb3 cluster in Nb3Cl8

Zimin Jiang et al.

Summary: Symmetry breaking of metal cluster-based strongly correlated systems can result in collective phenomena. In this study, the two-dimensional Nb-3 cluster compound Nb3Cl8 was found to undergo significant symmetry breaking and electron disproportionation under compression. A structural phase transition from trigonal P-3m1 to monoclinic C2/m was observed near 8 GPa, accompanied by a breaking of three-fold symmetry. The electron disproportionation on Nb-3 clusters, from delocalized Nb8/3+Nb8/3+Nb8/3+ to localized Nb3+Nb3+Nb2+, resulted in a subtle change in bandgap, as confirmed by electrical transport and UV-Vis absorption measurements.

SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY (2022)

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Article Materials Science, Multidisciplinary

Spectroscopic evidence of flat bands in breathing kagome semiconductor Nb3I8

Sabin Regmi et al.

Summary: This study presents spectroscopic evidence of flat and weakly dispersing bands in the breathing-kagome semiconductor Nb3I8, highlighting the sensitivity of these bands to the polarization of the incident photon beam. The findings contribute to understanding the interaction of geometry and electron correlations in two-dimensional materials.

COMMUNICATIONS MATERIALS (2022)

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Article Physics, Condensed Matter