Giant capacitance of a plane capacitor with a two-dimensional electron gas in a magnetic field

Abstract

If a clean two-dimensional electron gas (2DEG) with small concentration $n$ comprises one (or both) electrodes of a plane capacitor, the resulting capacitance $C$ can be larger than the "geometric capacitance" $C_g$ determined by the physical separation $d$ between electrodes. A recent paper [1] argued that when the effective Bohr radius $a_B$ of the 2DEG satisfies $a_B<<d$, one can achieve $C>>C_g$ at low concentration $n{d}^2<<1$. Here we show that even for devices with $a_B>d$, including graphene, for which $a_B$ is effectively infinite, one also arrives at $C>>C_g$ at low electron concentration if there is a strong perpendicular magnetic field.

6 pages, 5 figures; updated discussion about bilayer systems; added discussion of fractional quantum Hall states

References in corpus (8)

• Strong Coulomb drag and broken symmetry in double-layer graphene
• Density of states and zero Landau level probed through capacitance of graphene
• Thermodynamic density of states of two-dimensional GaAs systems near the apparent metal-insulator transition
• Nonlinear screening and percolative transition in a two-dimensional electron liquid
• Wigner crystal and bubble phases in graphene in the quantum Hall regime
• Large Negative Electronic Compressibility of LaAlO3-SrTiO3 Interfaces with Ultrathin LaAlO3 Layers
• Negative density of states: screening, Einstein relation, and negative diffusion
• A simple variational method for calculating energy and quantum capacitance of an electron gas with screened interactions

Cited by in corpus (6)

• Interaction phenomena in graphene seen through quantum capacitance
• Interaction-induced Interlayer Charge Transfer in the Extreme Quantum Limit
• Attraction of indirect excitons in van der Waals heterostructures with three semiconducting layers
• Chiral Wigner crystal phases induced by Berry curvature
• Correlation effects in the capacitance of a gated carbon nanotube
• Theory of cross quantum capacitance