Electric control of a $\{Fe_4\}$ single-molecule magnet in a single-electron transistor

TL;DR

This study uses first-principles calculations to show how an external electric field can control the magnetic anisotropy of a charged $ ext{Fe}_4$ single-molecule magnet in a single-electron transistor, aligning with experimental observations.

Contribution

It demonstrates the electric control of magnetic properties in a single-molecule magnet within a transistor setup, highlighting the influence of gate voltage on anisotropy and spin states.

Findings

Leads do not affect the neutral SMM's spin and anisotropy.

Charged states' anisotropy is strongly influenced by leads.

Gate voltage can tune the magnetic properties of the charged molecule.

Abstract

Using first-principles methods we study theoretically the properties of an individual $\{Fe_4\}$ single-molecule magnet (SMM) attached to metallic leads in a single-electron transistor geometry. We show that the conductive leads do not affect the spin ordering and magnetic anisotropy of the neutral SMM. On the other hand, the leads have a strong effect on the anisotropy of the charged states of the molecule, which are probed in Coulomb blockade transport. Furthermore, we demonstrate that an external electric potential, modeling a gate electrode, can be used to manipulate the magnetic properties of the system. For a charged molecule, by localizing the extra charge with the gate voltage closer to the magnetic core, the anisotropy magnitude and spin ordering converges to the values found for the isolated $\{Fe_4\}$ SMM. We compare these findings with the results of recent quantum transport experiments in three-terminal devices.