Olena Tkach
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View article: Time- and polarization-resolved extreme ultraviolet momentum microscopy
Time- and polarization-resolved extreme ultraviolet momentum microscopy Open
We report the development of an instrument combining an ultrafast, high-repetition-rate, polarization-tunable monochromatic extreme ultraviolet (XUV, 21.6 eV) beamline and a next-generation momentum microscope end station. This setup enabl…
View article: Time- and Polarization-Resolved Extreme Ultraviolet Momentum Microscopy
Time- and Polarization-Resolved Extreme Ultraviolet Momentum Microscopy Open
We report the development of an instrument combining an ultrafast, high-repetition-rate, polarization-tunable monochromatic extreme ultraviolet (XUV, 21.6 eV) beamline and a next-generation momentum microscope endstation. This setup enable…
View article: Floquet-Bloch valleytronics
Floquet-Bloch valleytronics Open
Upon time-periodic driving of electrons using electromagnetic fields, the emergence of Floquet-Bloch states enables the creation and control of exotic quantum phases. In transition metal dichalcogenides, broken inversion symmetry within ea…
View article: Spin polarization of the two-dimensional electron gas at the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi mathvariant="normal">EuO/SrTiO</mml:mi></mml:mrow><mml:mn>3</mml:mn></mml:msub></mml:math> (001) interface
Spin polarization of the two-dimensional electron gas at the (001) interface Open
Spin-polarized two-dimensional electron gases (2DEGs) are of particular interest for functional oxide electronics applications. The redox-created 2DEG residing on the strontium titanate, SrTiO3 (STO), side of a europium monoxide (EuO)/SrTi…
View article: Layered multiple scattering approach to Hard X-ray photoelectron diffraction: theory and application
Layered multiple scattering approach to Hard X-ray photoelectron diffraction: theory and application Open
Photoelectron diffraction (PED) is a powerful technique for resolving surface structures with sub-angstrom precision. At high photon energies, angle-resolved photoemission spectroscopy (ARPES) reveals PED effects, often challenged by small…
View article: Multimode objective lens for momentum microscopy and XPEEM: Theory
Multimode objective lens for momentum microscopy and XPEEM: Theory Open
The strong electric field between the sample and the extractor is at the heart of cathode lenses and a crucial factor for high resolution. However, fields in the range of 3-10 kV/mm can be a source of complications. Local field enhancement…
View article: Momentum microscopy with combined hemispherical and time-of-flight electron analyzers at the soft X-ray beamline I09 of the diamond light source
Momentum microscopy with combined hemispherical and time-of-flight electron analyzers at the soft X-ray beamline I09 of the diamond light source Open
The three-dimensional recording scheme of time-of-flight momentum microscopes (ToF-MMs) is advantageous for fast mapping of the photoelectron distribution in (E,k) parameter space over the entire Brillouin zone. However, the 2 ns pulse per…
View article: Ge$_{1-x}$Si$_{x}$ single crystals for Ge hole spin qubit integration
Ge$_{1-x}$Si$_{x}$ single crystals for Ge hole spin qubit integration Open
Spin qubits are fundamental building blocks of modern quantum computing devices. The path of Ge-based hole-spin qubits has several advantages over Si-based electron-spin systems, such as the absence of valley band degeneracy, the possibili…
View article: Floquet-Bloch Valleytronics
Floquet-Bloch Valleytronics Open
Driving quantum materials out-of-equilibrium makes it possible to generate states of matter inaccessible through standard equilibrium tuning methods. Upon time-periodic coherent driving of electrons using electromagnetic fields, the emerge…
View article: Layered Multiple Scattering Approach to Hard X-ray Photoelectron Diffraction: Theory and Application
Layered Multiple Scattering Approach to Hard X-ray Photoelectron Diffraction: Theory and Application Open
Photoelectron diffraction (PED) is a powerful and essential experimental technique for resolving the structure of surfaces with sub-angstrom resolution. In the high energy regime, researchers in angle-resolved photoemission spectroscopy (A…
View article: Spin polarization of the two-dimensional electron gas at the EuO/SrTiO$_3$ interface
Spin polarization of the two-dimensional electron gas at the EuO/SrTiO$_3$ interface Open
Spin-polarized two-dimensional electron gases (2DEGs) are of particular interest for functional oxide electronics applications. The redox-created 2DEG residing on the strontium titanate, SrTiO$_3$ (STO), side of a europium monoxide (EuO)/S…
View article: The electronic structure of EuPd$_2$Si$_2$ in the vicinity of the critical endpoint
The electronic structure of EuPd$_2$Si$_2$ in the vicinity of the critical endpoint Open
Hard X-ray angle-resolved photoemission spectroscopy reveals significant alterations in the valence band states of EuPd$_2$Si$_2$ at a temperature $T_V$, where the Eu ions undergo a temperature-induced valence crossover from a magnetic Eu$…
View article: Multi-Mode Lens for Momentum Microscopy and XPEEM: Theory
Multi-Mode Lens for Momentum Microscopy and XPEEM: Theory Open
The strong electric field between the sample and the extractor is the core of cathode lenses and a pivotal determinant of high resolution. Nevertheless, fields in the range of 3-8 kV/mm can be a source of complications. Local field enhance…
View article: Chirality in the Kagome Metal CsV$_3$Sb$_5$
Chirality in the Kagome Metal CsV$_3$Sb$_5$ Open
Using x-ray photoelectron diffraction (XPD) and angle-resolved photoemission spectroscopy, we study photoemission intensity changes related to changes in the geometric and electronic structure in the kagome metal CsV$_3$Sb$_5$ upon transit…
View article: Asymmetric electrostatic dodecapole: compact bandpass filter with low aberrations for momentum microscopy
Asymmetric electrostatic dodecapole: compact bandpass filter with low aberrations for momentum microscopy Open
Imaging energy filters in photoelectron microscopes and momentum microscopes use spherical fields with deflection angles of 90°, 180° and even 2 × 180°. These instruments are optimized for high energy resolution, and exhibit image aberrati…
View article: Hybrid Photoelectron Momentum Microscope at the Soft X-ray Beamline I09 of the Diamond Light Source
Hybrid Photoelectron Momentum Microscope at the Soft X-ray Beamline I09 of the Diamond Light Source Open
Soft X-ray momentum microscopy of crystalline solids is a highly efficient approach to map the photoelectron distribution in four-dimensional (E,k) parameter space over the entire Brillouin zone. The fixed sample geometry eliminates any mo…
View article: Observation of time-reversal symmetry breaking in the band structure of altermagnetic RuO <sub>2</sub>
Observation of time-reversal symmetry breaking in the band structure of altermagnetic RuO <sub>2</sub> Open
Altermagnets are an emerging elementary class of collinear magnets. Unlike ferromagnets, their distinct crystal symmetries inhibit magnetization while, unlike antiferromagnets, they promote strong spin polarization in the band structure. T…
View article: Analyzing core level photoelectrons by diffraction and circular dichroism via means of first-principle scattering calculations
Analyzing core level photoelectrons by diffraction and circular dichroism via means of first-principle scattering calculations Open
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View article: Doping-Induced Electronic and Structural Phase Transition in the Bulk Weyl Semimetal Mo1-xWxTe2
Doping-Induced Electronic and Structural Phase Transition in the Bulk Weyl Semimetal Mo1-xWxTe2 Open
A comprehensive study of the electronic and structural phase transition from 1T` to Td in the bulk Weyl semimetal Mo1-xWxTe2 at different doping concentrations has been carried out using time-of-flight momentum microscopy (including circul…
View article: Valence-transition-induced changes of the electronic structure in EuPd$_2$Si$_2$
Valence-transition-induced changes of the electronic structure in EuPd$_2$Si$_2$ Open
We present results of hard X-ray angle-resolved photoemission spectroscopy and photoemission diffraction measurements performed on high-quality single crystals of the valence transition compound EuPd$_2$Si$_2$ for temperatures 25~K $\leq$ …
View article: Influence of Bi doping on the electronic structure of (Ga,Mn)As epitaxial layers
Influence of Bi doping on the electronic structure of (Ga,Mn)As epitaxial layers Open
The influence of the addition of Bi to the (Ga,Mn)As dilute ferromagnetic semiconductor on its electronic structure as well as on its magnetic and structural properties has been studied. Epitaxial (Ga,Mn)(Bi,As) layers of high structural p…
View article: Magnetothermal Properties of Mesoscopic System Based on Ni<sub>3</sub>Pt Nanoparticle
Magnetothermal Properties of Mesoscopic System Based on Ni<sub>3</sub>Pt Nanoparticle Open
This article discusses the influence of the geometry of mesoscopic structures based on Ni3Pt nanoparticles on the magnetothermal characteristics to maximize the magnetocaloric response. Nanostructured samples in the form of arrays of nanoc…
View article: Magnetoresistive and Magnetooptical Properties of Double-component Film Alloys Based on Iron
Magnetoresistive and Magnetooptical Properties of Double-component Film Alloys Based on Iron Open
Представлені результати досліджень магнiторезистивних i магнітооптичних властивостей двокомпонентних плівкових систем на основі Fe і Pd, Pt або Ge, сформованих з рiзною концентрацiєю пара- або діамагнітної компоненти в одному технологiчном…
View article: Маgnetoresistive Effect in Granular Film Alloys Based on Ag and Fe or Со
Маgnetoresistive Effect in Granular Film Alloys Based on Ag and Fe or Со Open
У роботі наведені результати досліджень магніторезистивного ефекту в гранульованих плівкових сплавах на основі Ag і Fe або Со. Установлено, що при загальнiй концентрацiї атомiв немагнiтної ком- поненти вiд 15 до 68 ат. % в таких матеріалах…
View article: Physical Properties of Film Alloys Based on Ferromagnetic and Noble Metals (review). ІІ. Film Materials Based on Co and Ag or Au
Physical Properties of Film Alloys Based on Ferromagnetic and Noble Metals (review). ІІ. Film Materials Based on Co and Ag or Au Open
The results of analysis of literature and own results on the phase composition, electrophysical and
\nmagnetoresistive properties of film based granular alloys Co and Ag or Au. As between film systems based
\non Fe and Ag or Au and Co and …
View article: Physical Properties of Film Alloys Based on Ferromagnetic and Noble Metals (Review). І. Film Materials Based on Fe and Ag or Au
Physical Properties of Film Alloys Based on Ferromagnetic and Noble Metals (Review). І. Film Materials Based on Fe and Ag or Au Open
The results of analysis of literature and own data on the phase composition, electrophysical and magnetoresistive properties of granular film alloys based on Fe and Ag or Au are present. Analyzed the question about system designations of f…