Capacitance of graphene bilayer as a probe of layer- specific properties

Capacitance of graphene bilayer as a probe of layer-specific properties. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. The unique capabilities of capacitance measurements in bilayer graphene enable probing of layer-specific properties that are normally out of reach in transport measurements. Furthermore, capacitance measurements in the top-gate and penetration field geometries are sensitive to different physical quantities: The penetration field capacitance probes the two layers equally, whereas the top-gate capacitance preferentially samples the near layer, resulting in the " near-layer capacitance enhancement " effect observed in recent top-gate capacitance measurements. We present a detailed theoretical description of this effect and show that capacitance can be used to determine the equilibrium layer polarization, a potentially useful tool in the study of broken symmetry states in graphene, stemming from the interplay between interlayer screening, disorder, and the inverse-square-root van Hove singularity particular to the bilayer graphene band structure. We show how capacitance experiments can be used to probe the ground-state layer polarization, a potentially useful tool in the study of broken symmetry states in graphene.