Spektroskopie auf der atomaren Skala
Unsere Arbeitsgruppe nutzt und entwickelt verschiedene Rastersondenmikroskopieverfahren, um aktuelle Fragen der Grundlagenforschung zu beantworten.
Zurzeit forschen wir an folgenden Themen
- Ladungstransport in Graphen - Untersuchung mit Hilfe der Rastertunnelpoteniometrie
- Kondoeffekt an von einzelnen und gekoppelten magnetischen Störstellen
- Hexaboride und Iridate
- Metall Halbleiter-Grenzflächen mit Hilfe von Querschnittsrastertunnelmikroskopie
- Elektronische Eigenschaften von Dotieratomen in Halbleitern (GaAs, Si)
Charge transport in Graphen
Access to local transport properties
Electronic transport on a macroscopic scale is often described by
spatially averaged electric fields and scattering processes. To capture
electronic transport on the atomic scale, local and non-local
scattering processes need to be considered separately. An experimental
study based on low-temperature scanning tunneling potentiometry has
allowed us to separate different scattering mechanisms in graphene.
Most importantly, we are able to show that the voltage drop at a
monolayer/bilayer boundary is not located strictly at the structural
defect.
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Dynamic processes studied atom by
Atom - Combining pulsed optical exciation and STM/STS
Pump-probe experiments combined with SPM allow to resolve dynamic processes on the nanometer scale. We have utilized this to study the charging process of single donors in GaAs. Our experiments show that the combined dynamics of bound and free charges become important to better understand the physics of nano-scaled systems.
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Pump-probe experiments combined with SPM allow to resolve dynamic processes on the nanometer scale. We have utilized this to study the charging process of single donors in GaAs. Our experiments show that the combined dynamics of bound and free charges become important to better understand the physics of nano-scaled systems.
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Scanning tunneling spectroscopy
allows to study single magnetic impurities in bulk Crystals.This
surprising finding has opened up a new way to investigate the
interplay between the Ruderman-Kittel-Kasuya-Yosida
interaction and the Kondo effect, which is expected to provide the
driving force for the emergence of many phenomena in strongly
correlated electron materials. We have investigated iron dimers buried
below a Cu(100) surface by means of low-temperature scanning tunneling
spectroscopy. Two magnetic impurities in a metal are the smallest
possible system containing all these ingredients and define a bottom-up
approach towards a long-term under-standing of dense Systems.
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We have recently started two new
projects.
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