Local gate control of Mott metal-insulator transition in a 2D metal-organic framework

Abstract

Electron-electron interactions in materials lead to exotic many-body quantum phenomena including Mott metal-insulator transitions (MITs), magnetism, quantum spin liquids, and superconductivity. These phases depend on electronic band occupation and can be controlled via the chemical potential. Flat bands in two-dimensional (2D) and layered materials with a kagome lattice enhance electronic correlations. Although theoretically predicted, correlated-electron Mott insulating phases in monolayer 2D metal-organic frameworks (MOFs) with a kagome structure have not yet been realised experimentally. Here, we synthesise a 2D kagome MOF on a 2D insulator. Scanning tunnelling microscopy (STM) and spectroscopy reveal a MOF electronic energy gap of ~200 meV, consistent with dynamical mean field theory predictions of a Mott insulator. Combining template-induced (via work function variations of the substrate) and STM probe-induced gating, we locally tune the electron population of the MOF kagome bands and induce Mott MITs. These findings enable technologies based on electrostatic control of many-body quantum phases in 2D MOFs.

34 pages, 4 figures + SI 53 pages, 33 figures

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Cited by in corpus (6)

• Two-dimensional Kagome Materials: Theoretical Insights, Experimental Realizations, and Electronic Structures
• Breathing-Driven Metal-Insulator Transition in Correlated Kagome Systems
• Designing Topological High-Order Van Hove Singularities: Twisted Bilayer Kagomé
• Altermagnetism in an interacting model of Kagome materials
• Disentangling real space fluctuations: the diagnostics of metal-insulator transitions beyond single-particle spectral functions
• Collective Buckling in Metal-Organic Framework Materials