Electron Transport through SingleMn12Molecular Magnets

Abstract

We report transport measurements through a single-molecule magnet, the Mn 12 derivative Mn 12 O 12 O 2 C-C 6 H 4 -SAc 16 H 2 O 4 , in a single-molecule transistor geometry. Thiol groups connect the molecule to gold electrodes that are fabricated by electromigration. Striking observations are regions of complete current suppression and excitations of negative differential conductance on the energy scale of the anisotropy barrier of the molecule. Transport calculations, taking into account the high-spin ground state and magnetic excitations of the molecule, reveal a blocking mechanism of the current involving nondegenerate spin multiplets.

Nanogap Electrodes

“…Park and coworkers made outstanding achievements, which included the fabrication of single-electron transistors based on colloidal cadmium selenide nanocrystals, [84] providing evidence of nanomechanical oscillations of the C 60 molecule against the gold electrode in a single-C 60 transistor, [8] and observation of a Coulomb blockade and the Kondo effect in single-atom or single-molecule transistors. [30,36] Recently van der Zant et al have achieved a lot in this field, such as electron measurements through single molecular magnets, [92] observation of the Kondo effect in gold break junctions in the presence of magnetic impurities, [93] research on the temperature dependence of three-terminal molecular junctions based on sulfur endfunctionalized tercyclohexylidenes, [94] etc.…”

A Molecular Platinum Cluster Junction: A Single-Molecule Switch

“…Molecular metal clusters have recently started being explored in breakjunction type single-molecule-conductance experiments, [1][2][3] whilst previous studies have also investigated clusters in the STM-STS configuration which mantains a tunnel gap between the tip and the molecule. 4,5 Clusters have fewer metal atoms than metal nanoparticles but a more precisely defined composition and structure and as such they are better suited for comparative studies between theory and experiments.…”

Single-molecule transport in three-terminal devices

“…The third electrode can bring molecular levels into and out of resonance with the Fermi energy of the electrodes probing excited states and allowing different charge states to be accessed. Excited states can either be vibrational [10][11][12], electronic [13] or related to spin transitions [14,15]. These excitations serve as a fingerprint of the molecule under study.…”