A5009809682- Quantum and electron transport phenomena
- Magnetic properties of thin films
- Spectroscopy and Laser Applications
- Semiconductor Lasers and Optical Devices
- Molecular Junctions and Nanostructures
- Laser Design and Applications
- Advanced NMR Techniques and Applications
- Organic Light-Emitting Diodes Research
- nanoparticles nucleation surface interactions
- Atmospheric Ozone and Climate
- Atomic and Subatomic Physics Research
- Ferroelectric and Negative Capacitance Devices
- Physics of Superconductivity and Magnetism
- Advanced Memory and Neural Computing
- Semiconductor Quantum Structures and Devices
- Iron oxide chemistry and applications
- Magnetism in coordination complexes
- Photonic and Optical Devices
- Quantum-Dot Cellular Automata
- Theoretical and Computational Physics
- Diamond and Carbon-based Materials Research
- Surface and Thin Film Phenomena
- Electronic and Structural Properties of Oxides
- Conducting polymers and applications
- Magnetic and transport properties of perovskites and related materials
Johannes Gutenberg University Mainz
2022-2025
Massachusetts Institute of Technology
2020-2022
Eindhoven University of Technology
2021
University of Cambridge
2014-2020
PVD Products (United States)
2020
ETH Zurich
2008-2014
University of Freiburg
2014
Bridge University
2014
Technical University of Munich
2009
Universität Hamburg
2009
The observation of spin-dependent transmission electrons through chiral molecules has led to the discovery chiral-induced spin selectivity (CISS). remarkably high efficiency polarizing effect recently gained substantial interest due potential for future sustainable hybrid molecule magnetic applications. However, fundamental mechanisms underlying phenomena remain be understood fully. In this work, we explore impact chirality on angular momentum in metal/chiral thin-film heterostructures. For...
We present a model to priori calculate the temperature and field dependent intersubband linewidth of optical transition in quantum cascade laser designs. Besides intra- lifetime broadening, it comprises interface roughness scattering based on approach Tsujino et al. [Appl. Phys. Lett. 86, 062113 (2005)]. verified our with experimental data lasers having different linewidths. Excellent agreement experiment was found for two-phonon resonance design. Linewidths are slightly overestimated...
Electrical control of magnetic order in antiferromagnetic insulators (AFIs) using a Pt overlayer as spin current source has been recently reported, but detecting and understanding the nature current-induced switching AFIs remain challenge. Here, we examine origin Hall magnetoresistance-like signals measured standard bar geometry, which have taken evidence Pt/AFI bilayers. We show that transverse voltage consistent with both partial toggle Néel vector epitaxial Pt/NiO bilayers on Al2O3 are...
Magnetic skyrmions can be created and annihilated in ferromagnetic multilayers using single femtosecond infrared laser pulses above a material-dependent fluence threshold. From the perspective of applications, optical control offers route to faster and, potentially, more energy-efficient new class information-technology devices. Here, we investigate laser-induced skyrmion generation two different materials, mapping out dependence process on applied field fluence. We observe that sample...
A heterogeneous high-performance quantum-cascade laser gain chip comprising two bound-to-continuum active region designs emitting at 8.2 and 9.3 mum is presented. Its extrapolated spectrum has a full-width half-maximum (FWHM) of 350 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> . Though broad bandwidth invariably results in reduced cross section, devices with high-reflection coated...
Single-mode lasers operating at lambda ap 9 mum in continuous wave up to 423 K (150degC) were achieved by the combination of strong distributed-feedback coupling, a narrow gain active region design, low intersubband, and free-carrier losses as well good thermal management. Tuning 10 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> or 0.9% center frequency was heating device. The threshold current density varies from 1.1 kA/cm...
Singly linked and vinyl-linked dimers of dithienothiophenes exhibit different electronic behaviors. Single crystals the singly dimer show a high conductivity 0.265 S cm−1, five orders magnitude higher than that dimer. The huge increase in hole density results from formation radicals, which can be reversibly tuned by facile thermal de-doping. As service to our authors readers, this journal provides supporting information supplied authors. Such materials are peer reviewed may re-organized for...
Antiferromagnetic transition metal oxides are an established and widely studied materials system in the context of spin-based electronics, commonly used as passive elements exchange bias-based memory devices. Currently, major interest has resurged due to recent observation long-distance spin transport, current-induced switching, THz emission. As a result, insulating now considered be attractive candidates for active novel spintronic Here, we discuss some most promising systems highlight...
There is a growing interest in utilizing the distinctive material properties of organic semiconductors for spintronic applications. Here, we explore injection pure spin current from Permalloy into small molecule system based on dinaphtho[2,3-b:2,3-f]thieno[3,2-b]thiophene (DNTT) at ferromagnetic resonance. The unique tunability materials by molecular design allows us to study impact interfacial efficiency systematically. We show that both, interface as well diffusion length can be tuned...
We present transport experiments performed in high-quality quantum point contacts embedded a GaAs two-dimensional hole gas. The strong spin-orbit interaction results peculiar phenomena, including the previously observed anisotropic Zeeman splitting and level-dependent effective g factors. Here we find additional effects, namely, crossing anticrossing of spin-split levels depending on subband index magnetic field direction. Our experimental observations are reconciled heavy-hole Hamiltonian...
Antiferromagnets have recently been propelled to the forefront of spintronics by their high potential for revolutionizing memory technologies. For this, understanding formation and driving mechanisms domain structure is paramount. In this work, we investigate in a thin-film canted antiferromagnet $\alpha$-Fe$_2$O$_3$. We find that internal destressing fields domains do not follow crystal symmetry $\alpha$-Fe$_2$O$_3$, but fluctuate due substrate clamping. This leads an overall isotropic...
We demonstrate a spectrum demodulation technique allowing for rapid imaging in scanning nitrogen-vacancy center magnetometry. Our method relies on periodic excitation of the electron spin resonance by wide-band frequency sweeps at kilohertz rate combined with phase-locked detection photoluminescence signal. The is robust against changes shape and intensity, readily extended feedback to enable real-time tracking resonance. Fast magnetometry especially useful samples where signal dynamic range...
We perform low-temperature magneto-conductance measurements on Cu and Au thin films with adsorbed chiral molecules investigate their phase-coherent transport properties. Upon adsorption of molecules, the spin–orbit coupling strength in decreases become ferromagnetic as evident from weak localization antilocalization data. A theoretical model indicates that anisotropy molecular tilt angles, provided act magnetic moments, induces a nonvanishing exchange interaction, causing changes Au. Our...
Using a thermoelectric measurement, we demonstrate the nucleation and detection of single 360° homochiral Néel domain wall (DW), formed by an independently nucleated pair 180° DWs having same helicity in perpendicular magnetic anisotropy track. The DW formation is governed strong interfacial Dzyaloshinskii-Moriya interaction (DMI) detected at room temperature using anomalous Nernst effect (ANE). A large DMI can be generated interface where symmetry broken between material spin-orbit coupling...
Fiber coupled light output power of highly reliable single mode laser diodes with an emission wavelength around 980 nm has been increased by 40% as compared to former results. The devices reach in excess 1.3 W ex-facet CW up 60% conversion efficiency and exhibit a vertical far-field 21/spl deg/. maximum fiber amounts more than 700 mW. are designed satisfy the stringent requirements future cost efficient uncooled applications well high market broadband multi channel networks.
We report a surface-emitting THz source based on intracavity difference-frequency generation in dual-wavelength midinfrared quantum cascade lasers with integrated giant second-order nonlinear susceptibility. The light is coupled out of the waveguide by grating etched into laser ridges. In contrast to sources where radiation emitted from facet, this approach enables extraction emission whole length device even when coherence small. also studied properties mid-infrared pump beams and found...
One of the most powerful ways to manipulate spins in nanometer-scale devices is by converting a charge current spin via spin–orbit coupling. The resulting torques (SOTs) have been investigated and utilized extensively past decade. Quantitatively, however, SOTs may exhibit non-trivial angular dependence, which not well explored. Here, we develop nested iterative analysis determine magnitude from harmonic Hall measurements. This updated method largely improves fit quality full magnetic field...
Summary form only given. Organic semiconductors (OSC) such as conjugated polymers/molecules are enabling flexible, large area optoelectronic devices, organic light-emitting diodes, transistors, and solar cells. Due to their exceptionally long spin lifetimes, these carbon-based materials could also have an important impact on spintronics, where carrier spins play a key role in transmitting, processing storing information. Here, we combine three different approaches study transport OSC:...