Journal Article 2D ferroelectricity Lifshitz transition atomically thin materials chip‐scale FET arrays cold‐source field‐effect transistor dirac‐cone‐type energy band structure giant Stark effect grain boundary free graphene/IGZO hole carriers in Cu layered semimetals non-Fermi liquids nonlinear Hall effect phase diagrams phase transitions polymorphism resonant tunneling spectroscopy screening single‐crystal copper thin film sub‐60 mV dec−1 super‐steep subthreshold swing temperature-induced chemical potential shifts triangular hole orbit van der Waals heterostructures