Nearly Room-Temperature Ferromagnetism in a Pressure-Induced Correlated Metallic State of the van der Waals Insulator CrGeTe3

A complex interplay of different energy scales involving Coulomb repulsion, spin-orbit coupling, and Hund's coupling energy in 2D van der Waals (vdW) material produces a novel emerging physical state. For instance, ferromagnetism in vdW charge transfer insulator CrGeTe3 provides a promising platform to simultaneously manipulate the magnetic and electrical properties for potential device implementation using few nanometers thick materials. Here, we show a continuous tuning of magnetic and electrical properties of a CrGeTe3 single crystal using pressure. With application of pressure, CrGeTe3 transforms from a ferromagnetic insulator with Curie temperature TC∼66 K at ambient condition to a correlated 2D Fermi metal with TC exceeding ∼250 K. Notably, absence of an accompanying structural distortion across the insulator-metal transition (IMT) suggests that the pressure induced modification of electronic ground states is driven by electronic correlation furnishing a rare example of bandwidth-controlled IMT in a vdW material.