Research

The upper limit of conductance across metal-molecule junctions

The inherent electronic mismatch between molecules and metals is a general limitation for efficient electron transport in molecule-based electronics, including organic photovoltaic cells, organic light emitting diodes and single-molecule transistors. To date, the study of electronic transport across metal-molecule interfaces focused on low conductance governed by tunneling or hoping processes. Recently, we fabricated a series of highly transmitting single-molecule junctions in order to study the upper limit of conductance across metal-molecule interfaces. We revealed two fundamental mechanisms for conductance saturation near full electron transmission. These mechanisms can be used to optimize efficient charge injection, information transfer and recombination processes across metal-molecule interfaces (T. Yelin et al. Nature Materials 15, 444 (2016)).

Spin Transport in Atomic Chains

Spintronics takes advantage of the spin property of electrons to gain new electronic functions. Perhaps the most essential requirement for spin transport manipulations is the generation of highly spin-polarized currents governed by electrons of a single spin type. To date this challenge appeared to be far from reach at the nanoscale. Recently, we demonstrated the generation of up to 100% (with 2% uncertainty) spin-polarized current at the nanometer scale. The realization of complete spin filtering was achieved by orbital symmetry considerations in nickel-oxide (NiO) atomic chains (R. Vardimon et al. Nano Letters 15, 3894 (2015)).

Electron-Vibration Interaction in Kondo Molecular Junctions

We were able to turne on and off a Kondo many-body electronic system in a molecular junction by mechanical modifications of the metal-molecule interfaces . Thanks to this mechanical manipulation we found that molecular vibrations have an enhanced effect on electron transport when a many-body electronic system is activated. This is an unknown intriguing effect that have not been explained by theory (D. Rakhmilevitch et al. Physical Review Letters 113, 236603 (2014).

High and Tunable Molecular Anisotropic Magnetoresistance

When spin current is transmitted across metal-molecule interfaces it is very sensitive to the fine details of the interfacial electronic structure. We use this sensitivity to demonstrate significant enhancement of anisotropic magnetoresistance in molecular junctions. The important role of the metal-molecule orientation is exemplified and used for fine tuning of anisotropic magnetoresistance by mechanical means. The presented effect is based on local formation of half metallicity using interface properties (D. Rakhmilevitch et al. Nano Letters 16, 1741 (2016)).

Heat Dissipation and Thermopower in Nanoscale Conductors

The distribution of temperature across a nanoscale electronic conductor is related to many fundamental aspects as heat dissipation, the conversion of heat to electricity, and heat-pumping at the nanoscale. However, it is hard to probe temperature and temperature difference at the nanoscale. Consequently, many questions related to the mentioned subjects remained open. We develop local temperature probes to study the distribution of temperature across atomic and molecular conductors with the aim to demonstrate temperature related nanoscale phenomena, and efficient heat to electricity conversion at the nanoscale.