Orbital hybridization and electrostatic interaction in a double molecule transistor

TL;DR

This study demonstrates electrical control and probing of intermolecular interactions in a double molecule transistor, revealing orbital hybridization and electrostatic effects that influence charge transfer at the single-molecule level.

Contribution

It introduces a novel method to electrically manipulate and investigate intermolecular interactions in a double molecule transistor, advancing understanding of molecular electronics.

Findings

Electrostatic interaction observed when single electrons change in one molecule affect the other.

Orbital hybridization occurs under non-equilibrium conditions, enabling shared electron tunneling.

Electrical manipulation allows in situ probing of molecular interactions.

Abstract

Understanding the intermolecular interactions and utilize these interactions to effectively control the transport behavior of single molecule is the key step from single molecule device to molecular circuits1-6. Although many single molecule detection techniques are used to detect the molecular interaction at single-molecule level1,4,5,7,8, probing and tuning the intermolecular interaction all by electrical approaches has not been demonstrated. In this work, we successful assemble a double molecule transistor incorporating two manganese phthalocyanine molecules, on which we probe and tune the interaction in situ by implementing electrical manipulation on molecular orbitals using gate voltage. Orbital levels of the two molecules couple to each other and couple to the universal gate differently. Electrostatic interaction is observed when single electron changing in one molecule alters the transport behavior of the other, providing the information about the dynamic process of electron sequent tunneling through a molecule. Orbital hybridization is found when two orbital levels are put into degeneracy under non-equilibrium condition, making the tunneling electrons no longer localized to a specific molecule but shared by two molecules, offering a new mechanism to control charge transfer between non-covalent molecules. Current work offer a forelook into working principles of functional electrical unit based on single molecules.