Negative compressibility in MoS2 capacitance

TL;DR

This paper demonstrates significant capacitance enhancement in MoS2 FETs due to electron-electron interactions, with the strongest effects in monolayer and bilayer devices, highlighting potential for low-energy electronics.

Contribution

It reveals the negative compressibility effect in MoS2 and links it to electron interactions, providing new insights into 2D material capacitance behavior.

Findings

50% capacitance enhancement in monolayer MoS2

10% enhancement in bilayer MoS2

No significant enhancement in multilayer (>3 layers)

Abstract

Large capacitance enhancement is useful for increasing the gate capacitance of field-effect transistors (FETs) to produce low-energy-consuming devices with improved gate controllability. We report strong capacitance enhancement effects in a newly emerged two-dimensional channel material, molybdenum disulfide (MoS2). The enhancement effects are due to strong electron-electron interaction at the low carrier density regime in MoS2. We achieve about 50% capacitance enhancement in monolayer devices and 10% capacitance enhancement in bilayer devices. However, the enhancement effect is not obvious in multilayer (layer number >3) devices. Using the Hartree-Fock approximation, we illustrate the same trend in our inverse compressibility data.