Publications (34)
Analytical And Numerical Approximation of Effective Diffusivities in The Cytoplasm of Biological Cells
Michael Hanke, Marry-Chriz Cabauatan-Villanueva
The simulation of the metabolism in mammalian cells becomes a severe problem if spatial distributions must be taken into account. Especially the cytoplasm has a very complex geomet…
A high-precision abundance analysis of the nuclear benchmark star HD 20
Michael Hanke, Camilla Juul Hansen, Hans-Günter Ludwig +4
We present our chemical abundance investigation of the metal-poor ([Fe/H]=-1.60 dex), r-process-enriched ([Eu/Fe]=0.73 dex) halo star HD 20 using novel and archival high-resolution…
Plasma-assisted molecular beam epitaxy of NiO on GaN(00.1)
Melanie Budde, Thilo Remmele, Carsten Tschammer +8
The growth of NiO on GaN(00.1) substrates by plasma-assisted molecular beam epitaxy under oxygen rich conditions was investigated at growth temperatures between 100 C and…
Above-room-temperature ferromagnetism in large-area epitaxial Fe3GaTe2/graphene van der Waals heterostructures
Tauqir Shinwari, Kacho Imtiyaz Ali Khan, Hua Lv +10
Fe3GaTe2 (FGaT), a two-dimensional (2D) layered ferromagnetic metal, exhibits a high Curie temperature (TC) ~ 360 K along with strong perpendicular magnetic anisotropy (PMA), makin…
Current path in light emitting diodes based on nanowire ensembles
Friederich Limbach, Christian Hauswald, Jonas Lähnemann +8
Light emitting diodes (LEDs) were fabricated using ensembles of free-standing (In,Ga)N/GaN nanowires (NWs) grown on Si substrates in the self-induced growth mode by molecular beam…
Localization and defects in axial (In,Ga)N/GaN nanowire heterostructures investigated by spatially-resolved luminescence spectroscopy
Jonas Lähnemann, Christian Hauswald, Martin Wölz +4
(In,Ga)N insertions embedded in self-assembled GaN nanowires are of current interest for applications in solid state light emitters. Such structures exhibit a notoriously broad emi…
Towards a reliable implementation of least-squares collocation for higher-index differential-algebraic equations
Michael Hanke, Roswitha März
In this note we discuss several questions concerning the implementation of overdetermined least-squares collocation methods for higher-index differential algebraic equations (DAEs)…
Canonical Subspaces of Linear Time-Varying Differential-Algebraic Equations and Their Usefulness for Formulating Accurate Initial Conditions
Michael Hanke, Roswitha März
Accurate initial conditions have the task of precisely capturing and fixing the free integration constants of the flow considered. This is trivial for regular ordinary differential…
Purveyors of fine halos III. Chemical abundance analysis of a potential omega Cen associate
Andreas J. Koch-Hansen, Camilla Juul Hansen, Linda Lombardo +3
Globular clusters (GCs) are important donors to the build-up of the Milky Way (MW) stellar halo, having contributed at the ten percent level over the Galactic history. Stars that o…
Transmodal Analysis of Neural Signals
Yaroslav O. Halchenko, Michael Hanke, James V. Haxby +2
Localizing neuronal activity in the brain, both in time and in space, is a central challenge to advance the understanding of brain function. Because of the inability of any single…
Kinematics of outer halo globular clusters: M 75 and NGC 6426
Andreas Koch, Michael Hanke, Nikolay Kacharov
Globular clusters (GCs) and their dynamic interactions with the Galactic components provide an important insight into the structure and formation of the early Milky Way. Here, we p…
Research and Education in Computational Science and Engineering
Ulrich Rüde, Karen Willcox, Lois Curfman McInnes +30
Over the past two decades the field of computational science and engineering (CSE) has penetrated both basic and applied research in academia, industry, and laboratories to advance…
Brains on Beats
Umut Güçlü, Jordy Thielen, Michael Hanke +1
We developed task-optimized deep neural networks (DNNs) that achieved state-of-the-art performance in different evaluation scenarios for automatic music tagging. These DNNs were su…
ATHOS: On-the-fly stellar parameter determination of FGK stars based on flux ratios from optical spectra
Michael Hanke, Camilla Juul Hansen, Andreas Koch +1
Tools for the spectroscopic determination of fundamental stellar parameters should not only comprise customized solutions for one particular survey or instrument, but, in order to…
Diffraction at GaAs/FeSi core/shell nanowires: the formation of nanofacets
Bernd Jenichen, Michael Hanke, Maria Hilse +3
GaAs/FeSi core/shell nanowire structures were fabricated by molecular-beam epitaxy on oxidized Si(111) substrates and investigated by synchrotron x-ray diffraction. The surfa…
Proximity-tuned Magnetic and Transport Anomalies in All-epitaxial Fe5-xGeTe2/WSe2 Van der Waals Heterostructures
Hua Lv, Tauqir Shinwari, Kacho Imtiyaz Ali Khan +13
Van der Waals (vdW) heterostructures combining two-dimensional (2D) ferromagnets and semiconducting transition-metal dichalcogenides (TMDCs) offer highly promising opportunities fo…
On the computation of accurate initial conditions for linear higher-index differential-algebraic equations and its application in initial value solvers
Michael Hanke, Roswitha März
In contrast to regular ordinary differential equations, the problem of accurately setting initial conditions just emerges in the context of differential-algebraic equations where t…
The effect of the buffer layer coupling on the lattice parameter of epitaxial graphene on SiC(0001)
Timo Schumann, Martin Dubslaff, Myriano H. Oliveira +3
Grazing incidence X-ray diffraction (GID) was employed to probe the structure of atomically thin carbon layers on SiC(0001): a so-called buffer layer (BL) with a $6(\sqrt{3}\times\…
Chemical Evolution of R-process Elements in Stars (CERES). I. Stellar parameters and chemical abundances from Na to Zr
Linda Lombardo, Piercarlo Bonifacio, Patrick François +10
Aims. The Chemical Evolution of R-process Elements in Stars (CERES) project aims to provide a homogeneous analysis of a sample of metal-poor stars ([Fe/H]<-1.5). We present the ste…
Picosecond strain dynamics in GeSbTe monitored by time-resolved x-ray diffraction
Paul Fons, Peter Rodenbach, Kirill V. Mitrofanov +9
Coherent phonons (CP) generated by laser pulses on the femtosecond scale have been proposed as a means to achieve ultrafast, non-thermal switching in phase-change materials such as…
Questions concerning differential-algebraic operators: Toward a reliable direct numerical treatment of differential-algebraic equations
Michael Hanke, Roswitha März
The nature of so-called differential-algebraic operators and their approximations is constitutive for the direct treatment of higher-index differential-algebraic equations. We trea…
Tuning Structure and Magnetism in Large-Scale 2D Ferromagnet FeGeTe through Ni Doping
Kacho Imtiyaz Ali Khan, Tauqir Shinwari, Soheil Ershadrad +13
Two-dimensional ferromagnets with strong perpendicular magnetic anisotropy exhibit magnetic order down to the monolayer thickness, beneficial for energy-efficient spintronic device…
Influence of strain relaxation in axial (In,Ga)N/GaN nanowire heterostructures on their electronic properties
Oliver Marquardt, Thilo Krause, Vladimir Kaganer +3
We present a systematic study of the influence of elastic strain relaxation on the built-in electrostatic potentials and the electronic properties of axial (In,Ga)N/GaN nanowire he…
Quantum Diamond Microscopy for Non-Destructive Failure Analysis of an Integrated Fan-Out Package-on-Package iPhone Chip
Bartu Bisgin, Marwa Garsi, Andreas Welscher +2
The increasing complexity of advanced semiconductor packages, driven by chiplet architectures and 2.5D/3D integration, challenges conventional failure localization methods such as…
Counterintuitive strain distribution in axial (In,Ga)N/GaN nanowires
Thilo Krause, Michael Hanke, Oliver Brandt +1
We study the three-dimensional deformation field induced by an axial (In,Ga)N segment in a GaN nanowire. Using the finite element method within the framework of linear elasticity t…
Sharp periodic Ge concentration modulations beyond the conduction band valley wavevector in nuclear spin-free Si quantum wells
Ivo Rahlff, Carsten Richter, Martin Schmidbauer +13
Periodic Ge modulations within strained Si quantum wells in SiGe heterostructures offer a route to deterministically enhance conduction-band valley splitting in Si, a key requireme…
Purveyors of fine halos. II. Chemodynamical association of halo stars with Milky Way globular clusters
Michael Hanke, Andreas Koch, Zdenek Prudil +2
We present chemodynamical links between the present-day Milky Way halo field star population and Galactic globular clusters (GCs) using a dataset that combines information from the…
Large-area van der Waals epitaxy and magnetic characterization of FeGeTe films on graphene
J. Marcelo J. Lopes, Dietmar Czubak, Eugenio Zallo +8
Scalable fabrication of magnetic 2D materials and heterostructures constitutes a crucial step for scaling down current spintronic devices and the development of novel spintronic ap…
A least-squares collocation method for nonlinear higher-index differential-algebraic equations
Michael Hanke, Roswitha März
We introduce a direct numerical treatment of nonlinear higher-index differential-algebraic equations by means of overdetermined polynomial least-squares collocation. The procedure…
Neutron-capture elements in dwarf galaxies III: A homogenized analysis of 13 dwarf spheroidal and ultra-faint galaxies
Moritz Reichert, Camilla J. Hansen, Michael Hanke +3
We present a large homogeneous set of stellar parameters and abundances across a broad range of metallicities, involving classical dwarf spheroidal (dSph) and ultra-faint dSph…
On a variable step size modification of Hines' method in computational neuroscience
Michael Hanke
For simulating large networks of neurons Hines proposed a method which uses extensively the structure of the arising systems of ordinary differential equations in order to obtain a…
On the sensitivity of implementations of a least-squares collocation method for linear higher-index differential-algebraic equations
Michael Hanke
The present paper continues our investigation of an implementation of a least-squares collocation method for higher-index differential-algebraic equations. In earlier papers, we we…
Coexistence of quantum-confined Stark effect and localized states in an (In,Ga)N/GaN nanowire heterostructure
Jonas Lähnemann, Oliver Brandt, Carsten Pfüller +7
We analyze the emission of single GaN nanowires with (In,Ga)N insertions using both micro-photoluminescence and cathodoluminescence spectroscopy. The emission spectra are dominated…
The Orbit of the new Milky Way Globular Cluster FSR1716 = VVV-GC05
Rodrigo Contreras Ramos, Dante Minniti, Jose G. Fernandez-Trincado +10
We use deep multi-epoch near-IR images of the VISTA Variables in the Via Lactea (VVV) Survey to measure proper motions (PMs) of stars in the Milky Way globular cluster FSR1716 = VV…