Browsing by Author "Wolf, Daniel"

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Open Access
Data corresponding to the publication "Optical and acoustic plasmons in the layered material Sr2RuO4"
(Technische Universität Dresden, 2025-03-21) Schultz, Johannes; Lubk, Axel; Jerzembeck, Fabian; Kikugawa, Naoki; Knupfer, Martin; Wolf, Daniel; Büchner, Bernd; Fink, Jörg
We use momentum-dependent electron energy-loss spectroscopy in transmission to study collective charge excitations in the layer metal Sr2RuO4. This metal has a transition from a perfect Fermi liquid below T~30 K into a "strange" metal phase above T~800 K. We cover a complete range between in-phase and out-of-phase oscillations. Outside the classical range of electron-hole excitations, leading to a Landau damping, we observe well-defined plasmons. The optical (acoustic) plasmon due to an in-phase (out-of-phase) charge oscillation of neighbouring layers exhibits a quadratic (linear) positive dispersion. Using a model for the Coulomb interaction of the charges in a layered system, it is possible to describe the range of optical plasmon excitations at high energies in a mean-field random phase approximation without taking correlation effects into account. In contrast, resonant inelastic X-ray scattering data show at low energies an enhancement of the acoustic plasmon velocity due to correlation effects. This difference can be explained by an energy dependent effective mass which changes from ~ 3.5 at low energy to 1 at high energy near the optical plasmon energy. There are no signs of over-damped plasmons predicted by holographic theories.
Open Access
Supplemental material to "Field-induced condensation of π to 2π soliton lattices in chiral magnets"
(Technische Universität Dresden, 2026-06-30) Winter, Moritz; Pignedoli, Alessandro; Rahn, Marein; Sukhanov, Aleksandr; Achinuq, Barat; Bollard, Jack; Azhar, Maria; Everschor-Sitte, Karin; Pohl, Darius; Schneider, Sebastian; Tahn, Alexander; Victor, Ukleev; Valvidares, Manuel; Thomas, Andy; Wolf, Daniel; Vir, Praveen; Helm, Toni; van der Laan, Gerrit; Hesjedal, Thorsten; Geck, Jochen; Rellinghaus, Bernd
This dataset contains the experimental and simulation data underlying the figures of the corresponding publication, which reports a field-induced crossover from π to 2π chiral soliton lattices in the Heusler compound Mn1.4PtSn. All measurements were performed on the same focused-ion-beam lamella at room temperature, with the magnetic field applied out of plane (along the crystallographic c axis). The data are organized by method: (1) 1_LTEM — Lorentz transmission electron microscopy: transport-of-intensity (TIE) reconstructions of the magnetic phase and in-plane induction on a region of interest as a function of field (Figs 2, 3, 6), the two full-field raw micrographs at 0 and 300 mT shown in Fig 1, and the measured stripe period and domain widths vs field (Fig 3); (2) 2_REXS — resonant elastic X-ray scattering at the Mn L3 edge (Diamond I10): raw detector frames of the 0–550 mT field upsweep (Fig 1) and the extracted propagation-vector magnitude and harmonic intensities vs field (Figs 3, 4), with the analysis notebook; (3) 3_micromagnetics — Mumax3 input scripts and output (magnetization fields, energies, applied field) for the final field sweep that reproduces the measured modulation length, domain widths and harmonic content (Figs 6, 7, 8); (4) 4_model — a phenomenological 1D stripe-domain model (script, generated spin textures and induction profiles) used to deduce and visualize the spin textures (Figs 2g–o, 6); (5) figure_plots — the OriginPro projects holding the plotted data behind Figs 3, 4, 6 and 8. Together these data establish that the magnetic ground state of Mn1.4PtSn is a π-soliton lattice rather than a helical spiral, and that it condenses continuously into a conventional 2π-CSL under increasing out-of-plane field. A top-level README and Fig_to_data_map.csv document the file formats and the mapping between data and figures.