Spin Diode Behavior in Transport Through Single-Molecule Magnets

TL;DR

This paper investigates the spin diode behavior in single-molecule magnets by analyzing transport properties with different exchange couplings, revealing asymmetric current flow and tunable diode functionality based on molecular parameters.

Contribution

It introduces a detailed theoretical analysis of spin diode effects in SMMs, highlighting how exchange interactions influence transport asymmetry and device tunability.

Findings

Current is asymmetric with bias reversal, showing strong suppression at certain biases.

The diode functionality can be tuned by adjusting the LUMO level position.

The behavior depends on the type of exchange coupling (ferromagnetic or antiferromagnetic).

Abstract

We study transport properties of a single-molecule magnet (SMM) weakly coupled to one nonmagnetic and one ferromagnetic lead. Using the diagrammatic technique in real time, we calculate transport in the sequential and cotunneling regimes for both ferromagnetic and antiferromagnetic exchange coupling between the molecule's LUMO level and the core spin. We show that the current flowing through the system is asymmetric with respect to the bias reversal, being strongly suppressed for particular bias polarizations. Thus, the considered system presents a prototype of a SMM spin diode. In addition, we also show that the functionality of such a device can be tuned by changing the position of the molecule's LUMO level and strongly depends on the type of exchange interaction.