0000000000194852
AUTHOR
Sergey V. Chernov
Morphological and magnetic analysis of Fe nanostructures on W(110) by using scanning tunneling microscopy and Lorentz microscopy
Abstract We investigated morphological features and magnetic properties of epitaxial Fe nanostructures (films, stripes and nanoparticles) on a W(110) surface with monoatomic steps preferentially along the direction. The nanostructures were prepared in ultra-high vacuum by using electron-beam evaporation and subsequent annealing at different temperatures. Scanning tunneling microscopy measurements in-situ revealed elongated Fe nanostructures with aspect ratios of up to . The observable shape and orientation (along or perpendicular to the monoatomic steps of the substrate) of the nanostructures depended substantially on the preparation parameters. By capping the system with 7 monolayers of Pt…
Transmission electron microscopy investigation of oxidation of (110)NiAl single crystal with wedge-shaped profile
Abstract Low energy electron diffraction (LEED), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX), and electron energy loss spectroscopy (EELS) investigations of oxidation processes in (110)NiAl single crystal of wedge like shape, i.e., on the sample’s areas of different thickness, were carried out. It was found that in the result of several cycles of ion etching, annealing and oxidation the upper layer of (110)NiAl is enriched with Ni. With the increase of Ni concentration from 50 to 100 at. %, the stoichiometry of the near surface area changes and the new phases of Ni3Al and Ni with Al doping are formed one after another. Up to Ni content of 75 at. %…
Energy- and k -resolved mapping of the magnetic circular dichroism in threshold photoemission from Co films on Pt(111)
The magnetic circular dichroism in threshold photoemission (TPMCD) for perpendicularly magnetized fcc Co films on Pt(111) has been revisited. A complete mapping of the spectral function $I({E}_{B},{k}_{x},{k}_{y})$ (binding energy ${E}_{B}$, momentum parallel to surface ${k}_{x}$, ${k}_{y}$) and the corresponding TPMCD asymmetry distribution ${A}_{\mathrm{MCD}}({E}_{B},{k}_{x},{k}_{y})$ has been performed for one-photon and two-photon photoemission using time-of-flight momentum microscopy. The experimental results allow distinguishing direct from indirect transitions. The measurements reveal clear band features of direct transitions from bulk bands that show a nontrivial asymmetry pattern. …
Mapováni spinů povrchových a bulkových Rashba stavů v tenkých vrstvách feroelektrického α-GeTe(111)
Rozbíjení inverzní symetrie ve fereeleRashba efekt; Fotoemisse; DFTktrickém polovodiči způsobuje děleni stavů, tzv Rashba efekt. V tomto článku ukazujeme kompletně mapování spinové polarizace těchto Rashba stavů za pomoci spinovo rozlišené fotoemisse. The breaking of bulk inversion symmetry in ferroelectric semiconductors causes a Rashba-type spin splitting of electronic bulk bands. This is shown by a comprehensive mapping of the spin polarization of the electronic bands in ferroelectric α- GeTe(111) films using a time-of-flight momentum microscope equipped with an imaging spin filter that enables a simultaneous measurement of more than 10 000 data points. The experiment reveals an opposite…
Dirakův kužel a pseudogapped hustota stavů v topologické polovině Heuslerovy sloučeniny YPtBi
Topologické izolátory (Tis) jsou zajímavé materiály, které vykazují nebývalé vlastnosti. . Zde jsme prozkoumali sloučeniny YPtBi jako příklad ze třídy polovu-Heuslerových materiálů. Topological insulators (TIs) are exciting materials, which exhibit unprecedented properties, such as helical spinmomentum locking, which leads to large torques for magnetic switching and highly efficient spin current detection. Here we explore the compound YPtBi, an example from the class of half-Heusler materials, for which the typical band inversion of topological insulators was predicted. We prepared this material as thin films by conventional cosputtering from elementary targets. By in situ time-of-flight mo…
4D texture of circular dichroism in soft-x-ray photoemission from tungsten
Brief treatment and crisis intervention 21(1), 013017 (2019). doi:10.1088/1367-2630/aaf4cd