Capacitance and compressibility of heterostructures with strong electronic correlations

Abstract

Strong electronic correlations related to a repulsive local interaction suppress the electronic compressibility in a single-band model, and the capacitance of a corresponding metallic film is directly related to its electronic compressibility. Both statements may be altered significantly when two extensions to the system are implemented which we investigate here: (i) we introduce an attractive nearest-neighbor interaction $V$ as antagonist to the repulsive on-site repulsion $U$, and (ii) we consider nano-structured multilayers (heterostructures) assembled from two-dimensional layers of these systems. We determine the respective total compressibility $\kappa$ and capacitance $C$ of the heterostructures within a strong coupling evaluation, which builds on a Kotliar-Ruckenstein slave-boson technique. Whereas the capacitance $C(n)$ for electronic densities $n$ close to half-filling is suppressed---illustrated by a correlation induced dip in $C(n)$---it may be appreciably enhanced close to a van Hove singularity. Moreover, we show that the capacitance may be a non-monotonic function of $U$ close to half-filling for both attractive and repulsive $V$. The compressibility $\kappa$ can differ from $C$ substantially, as $\kappa$ is very sensitive to internal electrostatic energies which in turn depend on the specific set-up of the heterostructure. In particular, we show that a capacitor with a polar dielectric has a smaller electronic compressibility and is more stable against phase separation than a standard non-polar capacitor with the same capacitance.

References in corpus (6)

• Intrinsic instability of electronic interfaces with strong Rashba coupling
• Large Negative Electronic Compressibility of LaAlO3-SrTiO3 Interfaces with Ultrathin LaAlO3 Layers
• Fermi-liquid Landau parameters for a nondegenerate band: Spin and charge instabilities in the extended Hubbard model
• Exact results with the Kotliar-Ruckenstein slave-boson representation
• Phase separation and long wave-length charge instabilities in spin-orbit coupled systems
• Spin-orbit controlled quantum capacitance of a polar heterostructure

Cited by in corpus (4)

• Unconventional aspects of electronic transport in delafossite oxides
• Band-Gap-Dependent Electronic Compressibility of Carbon Nanotubes in the Wigner Crystal Regime
• Understanding the onset of negative electronic compressibility in one- and two-band 2D electron gases: Application to LaAlO${}_3$/SrTiO${}_3$
• Theory of cross quantum capacitance