Electric-Field-Induced Mott Insulating States in Organic Field-Effect Transistors

TL;DR

This paper explores how strong electron correlations can induce Mott insulating states in organic field-effect transistors, highlighting the conditions under which these states form and their stability against interlayer coupling and Coulomb interactions.

Contribution

It models the injected electrons in organic transistors using a Hubbard Hamiltonian and predicts the conditions for Mott insulator states in these systems.

Findings

Mott insulating states can form at specific fillings in organic transistors.

These states are unstable beyond certain interlayer coupling thresholds.

Long-range Coulomb interactions can destabilize the Mott states.

Abstract

We consider the possibility that the electrons injected into organic field-effect transistors are strongly correlated. A single layer of acenes can be modelled by a Hubbard Hamiltonian similar to that used for the kappa-(BEDT-TTF)(2)X family of organic superconductors. The injected electrons do not necessarily undergo a transition to a Mott insulator state as they would in bulk crystals when the system is half-filled. We calculate the fillings needed for obtaining insulating states in the framework of the slave-boson theory and in the limit of large Hubbard repulsion, U. We also suggest that these Mott states are unstable above some critical interlayer coupling or long-range Coulomb interaction.