Ligand-based transport resonances of single-molecule magnet spin filters: Suppression of the Coulomb blockade and determination of the orientation of the magnetic easy axis

TL;DR

This paper explores how ligand-supported transport resonances in single-molecule magnet transistors enable gate-controlled switching between Coulomb blockade and resonant tunneling, with implications for spin filtering and magnetic axis orientation detection.

Contribution

It predicts gate-controlled switching mechanisms and spin filtering effects in SMMTs, and links transport behavior to the magnetic easy axis orientation.

Findings

Ligand-supported transport resonances are present in Mn12-benzoate SMMs.

Gate control can switch between Coulomb blockade and resonant tunneling.

Strong spin filtering occurs in both transport regimes.

Abstract

We investigate single molecule magnet transistors (SMMTs) with ligands that support transport resonances. We find the lowest unoccupied molecular orbitals of Mn12-benzoate SMMs (with and without thiol or methyl-sulfide termination) to be on ligands, the highest occupied molecular orbitals being on the Mn12 magnetic core. We predict gate controlled switching between Coulomb blockade and coherent resonant tunneling in SMMTs based on such SMMs, strong spin filtering by the SMM in both transport regimes, and that if such switching is observed then the magnetic easy axis of the SMM is parallel to the direction of the current through the SMM.