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See detailSpielerischer Umgang mit Schrift und Sprache: Zugänge zum kreativen Schreiben
Andersen, Katja Natalie UL

in Praxis Grundschule (2010), 33(1), 43-45

Detailed reference viewed: 94 (3 UL)
See detailSpielzeugwelten
Andersen, Katja Natalie UL

in Duncker, Ludwig; Lieber, Gabriele (Eds.) Bildung in der Kindheit: Handbuch zum ästhetischen Lernen für Kindergarten und Grundschule (2009)

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See detailSpillovers to small business credit risk
Wolff, Christian UL

in Small Business Economics (2020)

Do large credit risk shocks spill over to small businesses and affect their real economic activity? Using information on small business credit risk, we find that small businesses show increased default ... [more ▼]

Do large credit risk shocks spill over to small businesses and affect their real economic activity? Using information on small business credit risk, we find that small businesses show increased default and bankruptcy rates following a shock to a customer industry. On an industry level, the shock to a customer industry is followed by a decrease in industry markups, disproportionate closure of firms, and cutbacks in inventories. Our analysis quantifies the elevated credit risk among small businesses and suggests a non-negligible 0.83% increase in expected losses on a diversified loan portfolio following a credit risk shock. This study provides banks and supervisors with greater clarity on timing and on the extent of elevated small business credit risk. It also allows them to assess the exposure of a bank portfolio to fluctuations in small business default rate. Such improved default prediction reduces credit rationing to the small business economy. [less ▲]

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See detailSpillovers to small business credit risk
Wolff, Christian UL

Report (2019)

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See detailSpin and charge currents induced by the spin Hall and anomalous Hall effects upon crossing ferromagnetic/nonmagnetic interfaces
Hönemann, Albert; Herschbach, Christian; Fedorov, Dmitry UL et al

in Physical Review. B (2019), 99

We start closing a gap in the comparison of experimental and theoretical data associated with the spin Hall effect. Based on a first-principles characterization of electronic structure and a semiclassical ... [more ▼]

We start closing a gap in the comparison of experimental and theoretical data associated with the spin Hall effect. Based on a first-principles characterization of electronic structure and a semiclassical description of electron transport, we compute the skew-scattering contribution to the transverse spin and charge currents generated by spin and anomalous Hall effect in a Co/Cu multilayer system doped with Bi impurities. The fact that the created currents cross the interface between the two materials strongly influences the efficiency of charge-to-spin current conversion, as demonstrated by our results. [less ▲]

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See detailSpin caloric transport from density-functional theory
Popescu, Voicu; Kratzer, Peter; Entel, Peter et al

in Journal of Physics: D Applied Physics (2019), 52

Spin caloric transport refers to the coupling of heat with spin transport. Its applications primarily concern the generation of spin currents and control of magnetisation by temperature gradients for ... [more ▼]

Spin caloric transport refers to the coupling of heat with spin transport. Its applications primarily concern the generation of spin currents and control of magnetisation by temperature gradients for information technology, known by the synonym spin caloritronics. Within the framework of ab initio theory, new tools are being developed to provide an additional understanding of these phenomena in realistic materials, accounting for the complexity of the electronic structure without adjustable parameters. Here, we review this progress, summarising the principles of the density-functional-based approaches in the field and presenting a number of application highlights. Our discussion includes the three most frequently employed approaches to the problem, namely the Kubo, Boltzmann, and Landauer–Büttiker methods. These are showcased in specific examples that span, on the one hand, a wide range of materials, such as bulk metallic alloys, nano-structured metallic and tunnel junctions, or magnetic overlayers on heavy metals, and, on the other hand, a wide range of effects, such as the spin-Seebeck, magneto-Seebeck, and spin-Nernst effects, spin disorder, and the thermal spin-transfer and thermal spin–orbit torques. [less ▲]

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See detailSpin disorder at Gd grain boundaries
Döbrich, Frank UL; Elmas, M.; Ferdinand, A. et al

in Europhysics News (2009), 40/3

Detailed reference viewed: 64 (2 UL)
See detailSpin fractionalization in topological insulators
Dolcetto, Giacomo UL

Presentation (2016, March 07)

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See detailSpin relaxation in a complex environment
Esposito, Massimiliano UL; Gaspard, P.

in Physical Review E (2003), 68(6),

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See detailSpin structure of nanocrystalline gadolinium
Michels, Andreas UL; Döbrich, Frank UL; Elmas, M. et al

in Europhysics Letters [=EPL] (2008), 81

We report on magnetic-field–dependent small-angle neutron scattering (SANS) experiments on nanocrystalline inert-gas condensed bulk Gd, which was synthesized using the low-capturing isotope 160Gd. The ... [more ▼]

We report on magnetic-field–dependent small-angle neutron scattering (SANS) experiments on nanocrystalline inert-gas condensed bulk Gd, which was synthesized using the low-capturing isotope 160Gd. The angular dependency of the scattering cross-section is in very good agreement with recent theoretical predictions. Rather unexpected for this type of material, we observe a "clover-leaf–shaped" anisotropy in the SANS signal, the origin of which is attributed to the existence of longitudinal magnetization fluctuations associated with atomic site disorder and modified coupling inside the defect cores of grain boundaries. [less ▲]

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See detailSpin structure of nanocrystalline terbium
Weissmüller, J.; Michels, Andreas UL; Michels, D. et al

in Physical Review. B, Condensed Matter and Materials Physics (2004), 69

We present an experimental study of the magnetic microstructure in the nanocrystalline hard magnet Tb. Field-dependent small-angle neutron scattering (SANS) data are analyzed quantitatively in terms of ... [more ▼]

We present an experimental study of the magnetic microstructure in the nanocrystalline hard magnet Tb. Field-dependent small-angle neutron scattering (SANS) data are analyzed quantitatively in terms of the correlation function of the spin misalignment. We find that up to applied fields of several tesla the magnetization remains “locked in” to the basal planes of the hcp crystal lattice of each individual crystallite, but that the in-plane orientation of the spins is highly nonuniform within each grain. This spin disorder at the nanoscale can be suppressed by a large applied field, but in the remanent state the disorder reduces the magnetization to values considerably below the Stoner limit. In field-dependent SANS, the intragrain spin disorder gives rise to a crossover of the scattering curves, and to the unusual finding that the scattering cross section at small scattering vector increases with increasing magnetic field. As the origin of the internal spin disorder within the grains, we propose an extra magnetic anisotropy energy at small grain size, presumably due to microstrain, a suggestion which is supported by analysis of ac-susceptibility data in the paramagnetic state. Our finding of a reduced remanence at small grain size is contrary to the remanence enhancement that is observed in other nanocrystalline hard magnets. We also report an unusual logarithmic field dependence of the magnetization over wide ranges of the applied field and temperature. [less ▲]

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See detailSpin structure of Nd-Fe-B-based textured nanocomposites:role of interface chemistry
Titov, Ivan UL; Michels, Andreas UL

Scientific Conference (2017, July 02)

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See detailSpin texture of generic helical edge states
Rod, Alexia UL; Schmidt, Thomas UL; Rachel, Stephan

in Physical Review B (2015), 91

We study the spin texture of a generic helical liquid, the edge modes of a two-dimensional topological insulator with broken axial spin symmetry. By considering honeycomb and square-lattice realizations ... [more ▼]

We study the spin texture of a generic helical liquid, the edge modes of a two-dimensional topological insulator with broken axial spin symmetry. By considering honeycomb and square-lattice realizations of topological insulators, we show that in all cases the generic behavior of a momentum-dependent rotation of the spin quantization axis is realized. Here we establish this mechanism also for disk geometries with continuous rotational symmetry. Finally, we demonstrate that the rotation of spin-quantization axis remains intact for arbitrary geometries, i.e., in the absence of any continuous symmetry. We also calculate the dependence of this rotation on the model and material parameters. Finally, we propose a spectroscopy measurement which should directly reveal the rotation of the spin-quantization axis of the helical edge states. [less ▲]

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See detailSpin texture of two-dimensional topological insulators
Rod, Alexia UL

Doctoral thesis (2017)

Since the discovery of two-dimensional topological insulators a decade ago, their one-dimensional edge states have attracted significant attention due to their unique properties. For example due to time ... [more ▼]

Since the discovery of two-dimensional topological insulators a decade ago, their one-dimensional edge states have attracted significant attention due to their unique properties. For example due to time-reversal symmetry, they are protected against elastic backscattering and they propagate such that electrons with opposite spins move in opposite directions. In fact, the only necessary symmetry to sustain the edge states is time-reversal symmetry. Moreover in experimental setups, the axial spin symmetry seems to be absent. This absence allows new processes to appear such as inelastic backscattering. However, these consequences were neglected in most theoretical works where the spins are considered to be polarized in the z direction. The aim of this thesis is to provide a more realistic model taking into account a broken axial spin symmetry. In this scheme, we show that a rotation of the spin quantization axis as a function of momentum always appears. This observation leads us to develop a deeper understanding of the size of the rotation related to the material parameters and material models, using also realistic values. It also leads us to understand the implications in real space in cases where translation invariance is lost and how to quantify the rotation in such systems. The new processes which arise when the axial spin symmetry is broken have important consequences for transport in real materials. To see this, we consider a Hall bar with a hole in its middle, i.e. an antidot. This enables us to create two tunneling regions in order to probe the effect of this generic model. We also consider the effect of Coulomb interactions around the hole, as they can be important in such geometry. We discover that it is possible to probe directly the absence of axial spin symmetry. As experimental evidence is important to investigate our theoretical findings, we propose spectroscopic means to probe the spin texture. Finally, we also consider one of the experimentally-known candidate materials, namely InAs/GaSb heterostructures. From the k.p Hamiltonian, it is possible to show that their bandstructure shows some anisotropies. The latter is also reflected in the spin texture of their edge states. [less ▲]

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See detailSpin textures and response functions of helical electron systems
Schmidt, Thomas UL

Scientific Conference (2016, July)

Detailed reference viewed: 33 (2 UL)
See detailSpin-charge coupling in correlated one-dimensional quantum systems
Schmidt, Thomas UL

Scientific Conference (2015, August)

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See detailSpin-charge separation in one-dimensional fermion systems beyond Luttinger liquid theory
Schmidt, Thomas UL; Imambekov, Adilet; Glazman, Leonid I.

in Phys. Rev. B (2010), 82

We develop a nonperturbative zero-temperature theory for the dynamic response functions of interacting one-dimensional spin-1/2 fermions. In contrast to the conventional Luttinger liquid theory, we take ... [more ▼]

We develop a nonperturbative zero-temperature theory for the dynamic response functions of interacting one-dimensional spin-1/2 fermions. In contrast to the conventional Luttinger liquid theory, we take into account the nonlinearity of the fermion dispersion exactly. We calculate the power-law singularities of the spectral function and the charge- and spin-density structure factors for arbitrary momenta and interaction strengths. The exponents characterizing the singularities are functions of momenta and differ significantly from the predictions of the linear Luttinger liquid theory. We generalize the notion of the spin-charge separation to the nonlinear spectrum. This generalization leads to phenomenological relations between threshold exponents and the threshold energy. [less ▲]

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See detailSpin-orbit coupling in quasi-one dimensional Wigner crystals
Kornich, Viktoriia UL; Pedder, Christopher UL; Schmidt, Thomas UL

in Physical Review. B: Condensed Matter and Materials Physics (2016)

Detailed reference viewed: 81 (0 UL)