Giant Gate Response of the Charge in an Electron-Lattice Condensate

TL;DR

This paper demonstrates that electron-lattice correlations in charge density wave materials can cause a giant gate response, significantly amplifying capacitance beyond geometric limits, with potential applications in ultra-scaled electronics.

Contribution

It reveals a novel giant gating phenomenon in CDW materials driven by electron-lattice interactions, expanding understanding of collective electronic effects on capacitance.

Findings

Gate-induced CDW charge change exceeds geometric predictions by 10-100 times.

Coupling to electron-lattice condensate amplifies gate response.

Quantified quantum capacitance and constructed band diagram for the device.

Abstract

Efficient electrical capacitive control is important for the next generation of ultra-low-power and ultra-fast electronics and energy-storage devices. Correlated electronic phases offer a powerful route to enhancing field-effect control beyond the limits of conventional capacitive gating. In such systems, modest gate voltages can couple to an order parameter, producing responses far larger than expected from the electrostatics of non-interacting carriers. It was demonstrated that electron-electron interactions, in which the exchange and correlation energies among electrons lower the chemical potential of an electron system as the electron density increases, can significantly increase the effective capacitance over its geometric capacitance value. Here, we show that the electron-lattice or electron-phonon correlations in charge density wave (CDW) condensate can lead to a giant gate response with the corresponding capacitance enhancement. This unusual phenomenon is demonstrated in the quasi-one-dimensional CDW material, where the gate-induced change in CDW charge density exceeds predictions based on geometrical gate capacitance by one to two orders of magnitude. This "giant gating" effect arises from the coupling of the electric field to the CDW electron-lattice condensate, demonstrating a mechanism for massively amplifying gate response via collective electronic behavior. We quantify the effect by determining the quantum capacitance of the CDW charge and by constructing a band diagram for the gated CDW device. The obtained results can lead to an alternative strategy for continuing the downscaling of the transistor feature size in electronic technology.