Spin diode behavior in transport through single-molecule magnets

¹  Faculty of Physics, Adam Mickiewicz University - 61-614 Poznań, Poland, EU
²  Physics Department, Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität München - 80333 München, Germany, EU
³  Institute of Molecular Physics, Polish Academy of Sciences - 60-179 Poznań, Poland, EU

Corresponding author: misiorny@amu.edu.pl

Received: 23 September 2009
Accepted: 8 December 2009

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.