A5049547894- Advanced Chemical Physics Studies
- Catalytic Processes in Materials Science
- Quantum and electron transport phenomena
- Semiconductor Lasers and Optical Devices
- Solid State Laser Technologies
- Laser Design and Applications
- Magnetic properties of thin films
- Laser Material Processing Techniques
- Ionic liquids properties and applications
- Terahertz technology and applications
- Semiconductor Quantum Structures and Devices
- Catalysts for Methane Reforming
- Semiconductor materials and devices
- Electrochemical Analysis and Applications
- Electronic and Structural Properties of Oxides
- nanoparticles nucleation surface interactions
- Molecular Junctions and Nanostructures
- Advanced optical system design
- Photonic and Optical Devices
- Heusler alloys: electronic and magnetic properties
- Gas Sensing Nanomaterials and Sensors
- Force Microscopy Techniques and Applications
- Groundwater flow and contamination studies
- Photonic Crystal and Fiber Optics
- Strong Light-Matter Interactions
Friedrich-Alexander-Universität Erlangen-Nürnberg
2008-2025
Universidade Nova de Lisboa
2021
Universität Innsbruck
2019-2021
University of Regensburg
2015-2018
DILAS (Germany)
2012-2018
Coherent (Germany)
2018
EMS (Switzerland)
2016
Leipzig University
2010
Heidelberg University
2004-2005
University of Stuttgart
2000-2005
Achieving control over light-matter interaction in custom-tailored nanostructures is at the core of modern quantum electrodynamics. In strongly and ultrastrongly coupled systems, excitation repeatedly exchanged between a resonator an electronic transition rate known as vacuum Rabi frequency ΩR. For ΩR approaching resonance ωc, novel phenomena including squeezed states, Dicke superradiant phase transitions, collapse Purcell effect, population ground state with virtual photon pairs are...
An ordered monolayer of phthalocyanine on a silver(111) surface reacts with the stoichiometric amount coadsorbed Fe atoms to form iron(II)-phthalocyanine. This surface-confined redox reaction was studied X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). The formation iron(II)-phthalocyanine confirmed by comparison directly deposited complex. No side reactions such as coordination peripheral nitrogen molecules were observed.
We review systematic experimental and theoretical efforts that explored formation, structure reactivity of PdZn catalysts for methanol steam reforming, a material recently proposed to be superior the industrially used Cu based catalysts. Experimentally, ordered surface alloys with Pd : Zn ratio ∼1 1 were prepared by deposition thin layers on Pd(111) characterized photoelectron spectroscopy low-energy electron diffraction. The valence band spectrum alloy resembles closely Cu(111), in good...
We report on the study of terahertz radiation-induced MIRO-like oscillations magnetoresistivity in GaAs heterostructures. Our experiments provide an answer two most intriguing questions---effect radiation helicity and role edges---yielding crucial information for understanding MIRO (microwave-induced resistance oscillations) origin. Moreover, we demonstrate that range materials exhibiting magneto-oscillations can be largely extended by using high-frequency radiation.
Ceria-based supported noble-metal catalysts release oxygen, which may help to reduce the formation of carbonaceous residues, for example during hydrocarbon reforming. To gain insight into microscopic origins these effects, a model study is performed under ultrahigh-vacuum conditions using single-crystal-based catalysts. The systems are based on ordered CeO(2)(111) films Cu(111), Pt nanoparticles grown by physical vapor deposition. growth and structure surfaces characterized means scanning...
We studied the first layer of ionic liquid (IL) 1‐3‐dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C1C1Im][Tf2N]) on Ag(111) under ultrahigh vacuum conditions using scanning‐tunneling and atomic‐force microscopy, compare observed results to behavior found Au(111), Cu(111) Pt(111). On Ag(111), we observe two stable phases, a stripe phase hexagonal phase. The phases Au(111) Pt(111) exhibit similar, checkerboard‐like structure with surface areas per ion pair ranging from 0.77 0.85...
Abstract The spin–orbit coupling (SOC) in semiconductors is strongly influenced by structural asymmetries, as prominently observed bulk crystal structures that lack inversion symmetry. Here we study an additional effect on the SOC: asymmetry induced large interface area between a nanowire core and its surrounding shell. Our experiments purely wurtzite GaAs/AlGaAs core/shell nanowires demonstrate optical spin injection into single free-standing determine effective electron g -factor of...
Ionic liquids (ILs) are used as ultrathin films in many applications. We studied the nanoscale arrangement within first layer of 1,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C1C1Im] [Tf2N]) on Au(111) between 400 and 110 K ultrahigh vacuum by scanning tunneling noncontact atomic force microscopy with molecular resolution. Compared to earlier studies similar ILs, a different behavior is observed, which we attribute small size symmetrical shape cation: (a) In both AFM STM only...
A large spin-dependent and electric field-tunable magnetoresistance of a two-dimensional electron system (2DES) is key ingredient for the realization many novel concepts spin-based electronic devices. The low observed during last decades in devices with lateral semiconducting (SC) transport channels between ferromagnetic (FM) source (S) drain (D) contacts has been main obstacle realizing spin field effect transistor proposals. Here, we show both, two terminal 2DES-based valve geometry, up to...
Soft x-ray magnetic circular dichroism (XMCD) spectra have been investigated for different crystallographic projections of CrO2. Strong anisotropic orbital Cr 3d contributions and a change sign the XMCD signal is observed attributed to t(2g) majority states near Fermi level. Additionally, moment analysis exhibits behavior in projected spin CrO2 assigned strong dipole term T(z), consistent with an intrinsic easy axis along [001] axis. A reduced isotropic has interpreted terms hybridization oxygen.
Understanding the growth of ultrathin films ionic liquids (ILs) on metal surfaces is highest relevance for a variety applications. We present detailed study wetting layer and successive multilayers 1,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C1C1Im][Tf2N]) Au(111). By atomic force microscopy (AFM) in ultrahigh vacuum, we follow temperature-dependent behavior between 110 300 K at defined coverages. initially observe formation with thickness ∼0.37 nm anions cations arranged...
Abstract We studied the adsorption and reaction behavior of ionic liquid (IL) 1,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C 1 C Im][Tf 2 N]) on Cu(111) using non-contact atomic force microscopy (nc-AFM), scanning tunneling (STM), angle-resolved X-ray photoelectron spectroscopy (ARXPS) in ultrahigh vacuum as a function temperature, supported by density-functional theory (DFT) calculations. Our nc-AFM results for sub-monolayer IL films show that at 200 K, self-assembles into...
Steps in the right direction: The role of steps removal sulfur from a Pt model catalyst, via metastable SO3 and SO4 species, was demonstrated by situ high-resolution X-ray photoelectron spectroscopy. From isothermal experiments activation energy rate-determining step deduced to be 34 kJ mol−1.
Abstract Histidine is an aromatic amino acid crucial for the biological functioning of proteins and enzymes. When matter exposed to ionising radiation, highly energetic particles interact with surrounding tissue which leads efficient formation low‐energy electrons. In present study, interaction electrons gas‐phase histidine studied at a molecular level in order extend knowledge electron‐induced reactions acids. We report both on positive ions formed by electron ionisation negative induced...
The adsorption and thermal evolution of ethene (ethylene) on clean oxygen precovered Ni(111) was investigated with high resolution x-ray photoelectron spectroscopy using synchrotron radiation at BESSY II. spectra allow to unequivocally identify the local environment individual carbon atoms. Upon 110 K, adsorbs in a geometry, where two atoms within intact molecule occupy nonequivalent sites, most likely hollow top; this new result unambiguously solves an old puzzle concerning geometry...
The demand for high-power and high-brightness fiber coupled diode laser devices is mainly driven by applications solid-state pumping materials processing. ongoing power scaling of lasers requires scalable fibercoupled with increased brightness. For in processing multi-kW output beam quality about 30 mm x mrad needed. We have developed a modular concept combining high power, brightness, wavelength stabilization optionally low weight, which becomes more important multitude applications. In...
We investigated growth and temperature stability of Pt nanoclusters from 1 to 50 atoms on h-BN/Rh(111) using high-resolution XPS STM.