Exploiting Negative Capacitance for Unconventional Coulomb Engineering

The many-body ground state of a two-dimensional electron system can be tuned by Coulomb engineering through control of the dielectric environment. However, in conventional dielectrics the static permittivity is restricted to positive values, limiting the accessible interaction regimes. Here we argue that the negative capacitance demonstrated in appropriately engineered structures can open new vistas for Coulomb engineering. The associated negative permittivity could transform the natural repulsive interaction of electrons into an attractive one, raising the intriguing possibility of nontrivial ground states, including superconductivity. Using models of two-dimensional electron systems with linear and parabolic dispersion relations coupled to environments with negative capacitance, we estimate the strength and sign of the engineered Coulomb interaction and outline parameter regimes that could stabilize correlated electronic phases.