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arXiv · 1501.05454

Superpoissonian shot noise in organic magnetic tunnel junctions

Juan Pedro Cascales·Jhen-Yong Hong·Isidoro Martinez·Minn-Tsong Lin·Tomasz Szczepanski·Vitalii K. Dugaev·Jozef Barnas·Farkad G. Aliev
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Abstract

Organic molecules have recently revolutionized ways to create new spintronic devices. Despite intense studies, the statistics of tunneling electrons through organic barriers remains unclear. Here we investigate conductance and shot noise in magnetic tunnel junctions with PTCDA barriers a few nm thick. For junctions in the electron tunneling regime, with magnetoresistance ratios between 10 and 40\%, we observe superpoissonian shot noise. The Fano factor exceeds in 1.5-2 times the maximum values reported for magnetic tunnel junctions with inorganic barriers, indicating spin dependent bunching in tunneling. We explain our main findings in terms of a model which includes tunneling through a two level (or multilevel) system, originated from interfacial bonds of the PTCDA molecules. Our results suggest that interfaces play an important role in the control of shot noise when electrons tunnel through organic barriers.

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Juan Pedro Cascales, Jhen-Yong Hong, Isidoro Martinez, Minn-Tsong Lin, Tomasz Szczepanski, Vitalii K. Dugaev, Jozef Barnas, Farkad G. Aliev. 2015-01-22. Superpoissonian shot noise in organic magnetic tunnel junctions. https://doi.org/10.1063/1.4903739

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