Explanipedia

Fermi surface and pseudogap in highly doped Sr2IrO4 Open

Y. Alexanian, A. de la Torre, S. McKeown Walker, M. Straub, G. Gatti , et al. · 2025

The fate of the Fermi surface in bulk electron-doped Sr 2 IrO 4 remains elusive, as does the origin and extension of its pseudogap phase. Here, we use high-resolution angle-resolved photoelectron spectroscopy (ARPES) to investigate the ele…

Spin polarization of the two-dimensional electron gas at the (001) interface Open

Paul Rosenberger, Andri Darmawan, O. Fedchenko, Olena Tkach, S. V. Chernov , et al. · 2025

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…

Percival soft X-ray CMOS Imager for Photon Science – Status and Prospects Open

M. Hajheidari, C. Wunderer, Jonathan Correa, A. Marras, J. S. Lange , et al. · 2025

Percival is a CMOS-based imager with 2 megapixels, also called P2M, designed for photon science experiments. The first generation of the P2M sensor showed some performance issues. Specifically, ADCs in full-speed operation mode are affecte…

Unlocking Exceptional Negative Valency and Spin Reconstruction in Non‐Collinear Anti‐Ferromagnetic Antiperovskite Mn<sub>3</sub>NiN Film Open

Aryan Keshri, Prasanna Das, Nayana Devaraj, Sourav Chowdhury, Jayjit Kumar Dey , et al. · 2025

Antiperovskite manganese nitrides have intriguing magnetic and electronic properties that are not well understood. Just as their perovskite oxide counterparts, they are expected to display properties tunable through epitaxial strain engine…

Magnetic x-ray spectroscopy of Gd-doped EuO thin films Open

E. Arnold, J. M. Riley, L. B. Duffy, A. I. Figueroa, R. Held , et al. · 2025

We present a detailed x-ray magnetic circular dichroism (XMCD) study of the magnetic properties of Gd-doped EuO thin films, synthesized via molecular-beam epitaxy with Gd doping levels up to over 12%. The impact of Gd doping on the electro…

Imaging Orbital Vortex Lines in Three-Dimensional Momentum Space Open

T. Figgemeier, M. Ünzelmann, Philipp Eck, Jakub Schusser, Lorenzo Crippa , et al. · 2025

We report the experimental discovery of orbital vortex lines in the three-dimensional (3D) band structure of a topological semimetal. Combining linear and circular dichroism in soft x-ray angle-resolved photoemission (SX-ARPES) with first-…

Strain tuning of oxygen vacancy channels in SrCoO2.5 thin films Open

Rajan Mishra, Shivam Choudhary, Sourav Chowdhury, Anju Ahlawat, Anupam Jana , et al. · 2025

Tuning of the oxygen vacancy channels (OVCs) ordering is crucial to control ionic conduction, which has much promise in energy materials and memory devices. Brownmillerite (BM) oxides have been proven to be an ideal playground for explorin…

Fermi surface and pseudogap in highly doped Sr$_{2}$IrO$_{4}$ Open

Y. Alexanian, A. de la Torre, Simon Walker, M. Straub, G. Gatti , et al. · 2024

The fate of the Fermi surface in bulk electron-doped Sr$_{2}$IrO$_{4}$ remains elusive, as does the origin and extension of its pseudogap phase. Here, we use high-resolution angle-resolved photoelectron spectroscopy (ARPES) to investigate …

Spin polarization of the two-dimensional electron gas at the EuO/SrTiO$_3$ interface Open

Paul Rosenberger, Andri Darmawan, O. Fedchenko, Olena Tkach, S. V. Chernov , et al. · 2024

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…

High-accuracy measurements of core-excited transitions in light Li-like ions Open

Moto Togawa, Steffen Kühn, Chintan Shah, V. A. Zaytsev, Natalia S. Oreshkina , et al. · 2024

The transition energies of the two 1s core-excited soft x-ray lines (dubbed q and r) from 1s22s1S1/2 to the respective upper levels 1s(2S)2s2p(3P)2P3/2 and 2P1/2 of Li-like oxygen, fluorine, and neon were measured and calibrated u…

High-accuracy Measurements of Core-excited Transitions in Light Li-like Ions Open

Moto Togawa, Steffen Kühn, Chintan Shah, Vladimir A. Zaystev, Natalia S. Oreshkina , et al. · 2024

The transition energies of the two $1s$-core-excited soft X-ray lines (dubbed q and r) from $1s^2 2s ^1S_{1/2}$ to the respective upper levels $1s(^{2}S)2s2p(^{3}P) ^{2}P_{3/2}$ and $^{2}P_{1/2}$ of Li-like oxygen, fluorine and neon were m…

Chirality in the Kagome Metal CsV$_3$Sb$_5$ Open

H. J. Elmers, Olena Tkach, Y. Lytvynenko, Priyanka Yogi, Matthias Schmitt , et al. · 2024

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…

High-precision Transition Energy Measurements of Neon-like Fe xvii Ions Open

Chintan Shah, Moto Togawa, Marc Botz, Jonas Danisch, Joschka Goes , et al. · 2024

We improve by a factor of 4–20 the energy accuracy of the strongest soft X-ray transitions of Fe xvii ions by resonantly exciting them in an electron beam ion trap with a monochromatic beam at the P04 beamline of the PETRA III synchrotron …

Natural-linewidth measurements of the and soft-x-ray transitions in Ni xix Open

Chintan Shah, Steffen Kühn, S. Bernitt, René Steinbrügge, Moto Togawa , et al. · 2024

We used the monochromatic soft-x-ray beamline P04 at the synchrotron-radiation facility PETRA III to resonantly excite the strongest 2p−3d transitions in neonlike Ni ions, [2p6]J=0→[(2p5)1/23d3/2]J=1 and [2p6]J=0→[(2p5)3/23d5/2]J=1, respec…

Chirality-Driven Orbital Angular Momentum and Circular Dichroism in CoSi Open

Stefanie Suzanne Brinkman, Xin Tan, Bjørnulf Brekke, Anders Christian Mathisen, Øyvind Finnseth , et al. · 2024

Chiral crystals and molecules were recently predicted to form an intriguing platform for unconventional orbital physics. Here, we report the observation of chirality-driven orbital textures in the bulk electronic structure of CoSi, a proto…

A compact approach to higher-resolution resonant inelastic x-ray scattering detection using photoelectrons Open

Jan O. Schunck, Jens Buck, Robin Y. Engel, Simon R. Kruse, Simon Marotzke , et al. · 2024

The detection of inelastically scattered soft x-rays with high energy resolution usually requires large grating spectrometers. Recently, photoelectron spectrometry for analysis of x-rays (PAX) has been rediscovered for modern spectroscopy …

Chirality-Driven Orbital Angular Momentum and Circular Dichroism in CoSi Open

Stefanie Suzanne Brinkman, Xin Tan, Bjørnulf Brekke, Anders Christian Mathisen, Øyvind Finnseth , et al. · 2024

Chiral crystals and molecules were recently predicted to form an intriguing platform for unconventional orbital physics. Here, we report the observation of chirality-driven orbital textures in the bulk electronic structure of CoSi, a proto…

A new pathway to correlate the octahedral tilt coupling and spin-orbit reconstruction at oxide interfaces Open

Sujit Das, Jayjit Kumar Dey, Koushik Jagadish, Arka Bandyopadhyay, Sourav Chowdhury , et al. · 2024

The direct experimental probing and detailed imaging of octahedral tilt, along with the control of magnetic ground state and spin-orbit occupancies in an artificially engineered heterointerface through the manipulation of strain via interf…

Tomographic Imaging of Orbital Vortex Lines in Three-Dimensional Momentum Space Open

T. Figgemeier, M. Ünzelmann, Philipp Eck, Jakub Schusser, Lorenzo Crippa , et al. · 2024

We report the experimental discovery of orbital vortex lines in the three-dimensional (3D) band structure of a topological semimetal. Combining linear and circular dichroism in soft x-ray angle-resolved photoemission (SX-ARPES) with first-…

Observation of time-reversal symmetry breaking in the band structure of altermagnetic RuO <sub>2</sub> Open

O. Fedchenko, J. Minář, Akashdeep Akashdeep, S. W. D’Souza, D. Vasilyev , et al. · 2024

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…

Multi-Mode Front Lens for Momentum Microscopy: Part II Experiments Open

O. Tkach, Sotirios Fragkos, Quang Phú Nguyễn, S. V. Chernov, Markus Scholz , et al. · 2024

We have experimentally demonstrated different operating modes for the front lenses of the momentum microscopes described in Part I. Measurements at energies from vacuum UV at a high-harmonic generation (HHG)-based source to the soft and ha…

High-Precision Transition Energy Measurements of Neon-like Fe XVII Ions Open

Chintan Shah, Moto Togawa, Marc Botz, Jonas Danisch, Joschka Goes , et al. · 2024

We improve by a factor of 4-20 the energy accuracy of the strongest soft X-ray transitions of Fe XVII ions by resonantly exciting them in an electron beam ion trap with a monochromatic beam at the P04 beamline of the PETRA III synchrotron …

Orbital-selective metal skin induced by alkali-metal-dosing Mott-insulating Ca2RuO4 Open

Masafumi Horio, Filomena Forte, D. Sutter, Minu Kim, C. G. Fatuzzo , et al. · 2023

Doping-Induced Electronic and Structural Phase Transition in the Bulk Weyl Semimetal Mo1-xWxTe2 Open

O. Fedchenko, Florian Diekmann, Philipp Rüßmann, M. Kallmayer, Lukas Odenbreit , et al. · 2023

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…

Fluctuation, insulation and superconductivity: the pressure-dependent phase-diagram of Rb$_2$Mo$_6$Se$_6$ Open

Yongsheng Zhao, A. P. Petrović, P. Gougeon, Philippe Le Gall, Kai Chen , et al. · 2023

The quasi-one-dimensional (q1D) material Rb$_2$Mo$_6$Se$_6$ has been proposed to display a nontrivial combination of low-dimensional fluctuations and a dynamical charge density wave (CDW) at ambient pressure. This may lead to a progressive…

Active sites of Te-hyperdoped silicon by hard x-ray photoelectron spectroscopy Open

Moritz Hoesch, O. Fedchenko, Mao Wang, Christoph Schlueter, Dmitrii V. Potorochin , et al. · 2023

Multiple dopant configurations of Te impurities in close vicinity in silicon are investigated using photoelectron spectroscopy, photoelectron diffraction, and Bloch wave calculations. The samples are prepared by ion implantation followed b…

Circular dichroism in hard X-ray photoelectron diffraction observed by time-of-flight momentum microscopy Open

Olena Tkach, Trung-Phuc Vo, O. Fedchenko, K. Medjanik, Y. Lytvynenko , et al. · 2023

Active Sites of Te-hyperdoped Silicon by Hard X-ray Photoelectron Spectroscopy Open

Moritz Hoesch, O. Fedchenko, Mao Wang, Christoph Schlueter, Dmitrii V. Potorochin , et al. · 2023

Multiple dopant configurations of Te impurities in close vicinity in silicon are investigated using photoelectron spectroscopy, photoelectron diffraction, and Bloch wave calculations. The samples are prepared by ion implantation followed b…

New Measurement Resolves Key Astrophysical Fe XVII Oscillator Strength Problem Open

Steffen Kühn, Charles Cheung, Natalia S. Oreshkina, René Steinbrügge, Moto Togawa , et al. · 2022

One of the most enduring and intensively studied problems of x-ray astronomy is the disagreement of state-of-the art theory and observations for the intensity ratio of two Fe XVII transitions of crucial value for plasma diagnostics, dubbed…

X-Ray Photoabsorption of Density-sensitive Metastable States in Ne vii, Fe xxii, and Fe xxiii Open

René Steinbrügge, Steffen Kühn, F. Nicastro, M. F. Gu, Moto Togawa , et al. · 2022

Metastable states of ions can be sufficiently populated in absorbing and emitting astrophysical media, enabling spectroscopic plasma-density diagnostics. Long-lived states appear in many isoelectronic sequences with an even number of elect…

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