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Séminaire de Deung-Jang CHOI (13 juin 2014)
Max Planck Research Group-Dynamics of Nanoelectronic Systems, Center for Free-Electron Laser Science, Hamburg, Germany
Spin injection and detection at the atomic scale
with a single Kondo impurity
I will present the first low-temperature STM measurements showing a Kondo splitting of a single atom in the presence of a spin-polarized current. A cobalt atom on the Cu(100) surface presents a Kondo resonance, which we are able to split by approaching a magnetic tip covered by copper. The junction formed with such a tip corresponds to a rudimentary giant magneto-resistance (GMR) structure. The splitting of the Kondo resonance observed with this tip is then assigned to a spin-polarized current flowing across the non-magnetic material.
I will then focus on a functionalized molecular C60 tip and show how it may be potentially interesting for probing a Kondo system. Recently, functionalized tips built by picking up molecules such as CO or H2 have been employed to obtain an enhanced resolution in STM images. After presenting how to prepare and characterize a C60 tip, I will detail how a C60-terminated tip can be used to detect and alter the Kondo effect of Co on Cu(100). This work is a prerequisite for studying molecular point contacts exhibiting a Kondo effect.
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