A5044234133- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Electronic and Structural Properties of Oxides
- Rare-earth and actinide compounds
- Physics of Superconductivity and Magnetism
- Inorganic Chemistry and Materials
- Iron-based superconductors research
- Perovskite Materials and Applications
- Transition Metal Oxide Nanomaterials
- X-ray Diffraction in Crystallography
- Semiconductor materials and devices
- Catalysis and Oxidation Reactions
- Electron and X-Ray Spectroscopy Techniques
- Advancements in Battery Materials
- Luminescence Properties of Advanced Materials
- Nuclear Materials and Properties
- Multiferroics and related materials
- Topological Materials and Phenomena
- Advanced Thermoelectric Materials and Devices
- Metal Extraction and Bioleaching
- Fusion materials and technologies
- Thermal Radiation and Cooling Technologies
- Advanced Materials Characterization Techniques
- Radioactive element chemistry and processing
- Machine Learning in Materials Science
Max Planck Institute for Chemical Physics of Solids
2017-2025
Waseda University
2024-2025
Max Planck Society
2023
Universitat Autònoma de Barcelona
2019
CeRh2As2 is a new multiphase superconductor with strong suggestions for an additional itinerant multipolar ordered phase. The modeling of the low-temperature properties this heavy-fermion compound requires quartet Ce3+ crystal-field ground state. Here, we provide evidence formation such state using x-ray spectroscopy. Core-level photoelectron and absorption spectroscopy confirm presence Kondo hybridization in CeRh2As2. temperature dependence linear dichroism unambiguously reveals impact...
We have investigated the electronic structure of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>La</a:mi><a:mn>3</a:mn></a:msub><a:msub><a:mi>Ni</a:mi><a:mn>2</a:mn></a:msub><a:msub><a:mi mathvariant="normal">O</a:mi><a:mrow><a:mn>7</a:mn><a:mo>−</a:mo><a:mi>δ</a:mi></a:mrow></a:msub></a:mrow></a:math> <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mo>(</c:mo><c:mi>δ</c:mi><c:mo>≈</c:mo><c:mn>0.07</c:mn><c:mo>)</c:mo></c:mrow></c:math> by means...
Frustrated magnets offer a plethora of exotic magnetic ground states, including quantum spin liquids (QSLs), in which enhanced fluctuations prevent long-range ordering the strongly correlated spins down to lowest temperature. Here we have investigated trimer based mixed valence hexagonal rhodate <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>Ba</a:mi><a:mn>4</a:mn></a:msub><a:msub><a:mi>NbRh</a:mi><a:mn>3</a:mn></a:msub><a:msub><a:mi...
We present an experimental investigation of the magnetic ground state in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>Ba</a:mi><a:mn>4</a:mn></a:msub><a:msub><a:mi>NbIr</a:mi><a:mn>3</a:mn></a:msub><a:msub><a:mi mathvariant="normal">O</a:mi><a:mn>12</a:mn></a:msub></a:mrow></a:math>, a fractional valent trimer iridate. X-ray absorption and photoemission spectroscopy show that Ir valence lies between <c:math...
X-ray magnetic circular dichroism provides a means to identify ferromagnetic, chiral, and altermagnetic orders via their time-reversal-symmetry ($\mathcal{T}$) breaking. However, differentiating domains related by crystallographic symmetries remains technical challenge. Here we reveal (CD) in the resonant inelastic x-ray scattering (RIXS) spectra from MnTe. The azimuthal dependence of RIXS-CD intensity magnon excitations indicates dominant occupation single domain. our geometry is ascribed...
We examine the bulk electronic structure of Nd3Ni2O7 using Ni 2p core-level hard x-ray photoemission spectroscopy combined with density functional theory + dynamical mean-field theory. Our results reveal a large deviation 3d occupation from formal Ni2.5+ valency, highlighting importance charge-transfer oxygen ligands. find that dominant d8 configuration is accompanied by nearly equal contributions d7 and d9 states, exhibiting an unusual valence state among Ni-based oxides. Finally, we...
We examine the bulk electronic structure of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>Nd</a:mi><a:mn>3</a:mn></a:msub><a:msub><a:mi>Ni</a:mi><a:mn>2</a:mn></a:msub><a:msub><a:mi mathvariant="normal">O</a:mi><a:mn>7</a:mn></a:msub></a:mrow></a:math> using Ni <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mn>2</c:mn><c:mi>p</c:mi></c:mrow></c:math> core-level hard x-ray photoemission spectroscopy combined with density functional theory <d:math...
Significance The interplay of band-formation and electron-correlation effects in uranium heavy fermion compounds is the subject an ongoing debate. Here unexpected insight has been gained from advanced spectroscopies on isostructural members U <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> <mml:mi mathvariant="normal">S</mml:mi> mathvariant="normal">i</mml:mi> </mml:math> family...
Experiments show that lattice relaxations play a role in the gradual spin-state and insulator-to-metal transitions of LaCoO${}_{3}$. The findings call for reconsideration transition energetics this related materials.
A procedure for quantifying the U <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>5</a:mn><a:mi>f</a:mi></a:mrow></a:math> electronic covalency and degree of localization in intermetallic compounds is presented. To this end, bulk sensitive hard soft x-ray photoelectron spectroscopy were utilized combination with density-functional theory (DFT) plus dynamical mean-field (DMFT) calculations. The energy dependence photoionization cross sections allows disentanglement <b:math...
Here we report on our study to quantitatively describe the intensities of valence band hard x-ray photoemission spectra (HAXPES) a rare earth element containing $3d$ transition metal oxides. Using ${\mathrm{LaCoO}}_{3}$ as representative model compound, compared experimental data results ab initio one-step structure calculations well sum partial density states atomic constituents weighted by their tabulated photoionization cross sections. We discovered that semicore La $5p$ surprisingly...
The electronic structure of ${\mathrm{FeWO}}_{4}$ is studied by photoelectron spectroscopy at x-ray and hard photon energies on high-quality single crystals. Photoionization cross-section effects together with full atomic multiplet configuration interaction band calculations allow us to identify the contributions iron tungsten valence band. analysis shows that correlations in necessitate theoretical approaches beyond standard models even for description a formal $5{d}^{0}$ configuration.
We investigated the electronic structure of ${\mathrm{BaEu}}_{2}{\mathrm{Nb}}_{5}{\mathrm{O}}_{15}$ and ${\mathrm{Eu}}_{3}{\mathrm{Nb}}_{5}{\mathrm{O}}_{15}$ by means hard x-ray photoelectron spectroscopy. The Eu $3d$ core level spectra are primarily dominated ${\mathrm{Eu}}^{2+}$ signals. well-screened feature in Nb is suppressed ${\mathrm{Eu}}_{3}{\mathrm{Nb}}_{5}{\mathrm{O}}_{15}$, consistent with insulating behavior due to atomic disorder and/or rattling effect small ions spacious $A2$...
We investigate the topological superconductor candidate <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mi>UTe</a:mi><a:mn>2</a:mn></a:msub></a:math> using high-resolution valence-band resonant inelastic x-ray scattering at U <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msub><b:mi>M</b:mi><b:mrow><b:mn>4</b:mn><b:mo>,</b:mo><b:mn>5</b:mn></b:mrow></b:msub></b:math> edges. observe atomiclike low-energy excitations that support correlated nature of this...
Evidence of the Kondo effect---a hallmark interacting electrons---in a transition-metal oxide provides new insight into rich electronic behavior these materials and platform for studying correlated physics.
We investigated the electronic structure of vacancy-ordered $4d$-transition-metal monoxide $\mathrm{NbO}\phantom{\rule{0.28em}{0ex}}({\mathrm{Nb}}_{3}{\mathrm{O}}_{3})$ using angle-integrated soft- and hard-x-ray photoelectron spectroscopies as well ultraviolet angle-resolved spectroscopy. found that density-functional-based band-structure calculations can describe spectral features accurately provided self-interaction effects are taken into account. In spectra we were able to identify...
We have studied the ${\mathrm{Ti}}^{3+}/{\mathrm{Ti}}^{4+}$ mixed valence state in Mg-doped ${\mathrm{Ti}}_{2}{\mathrm{O}}_{3}$ using hard x-ray photoemission spectroscopy. The Ti $2p$ spectrum for corundum-type revealed ${\mathrm{Ti}}^{3+}$ configuration with strong electronic coupling $c$-axis Ti-Ti pairs whereas data ilmenite-type ${\mathrm{MgTiO}}_{3}$ confirmed ${\mathrm{Mg}}^{2+}\text{\ensuremath{-}}{\mathrm{Ti}}^{4+}$ charge cation pairs. In...
The interplay of Kondo screening and magnetic ordering in strongly correlated materials containing local moments is a subtle problem. Usually the number conduction electrons per unit cell matches or exceeds moments, Kondo-screened heavy Fermi liquid develops at low temperatures. Changing pressure, field, chemical doping can displace this favor magnetically ordered state. Alternatively, singlet formation be suppressed when small compared to known as exhaustion scenario. Here we report...
We report hard x-ray photoelectron spectroscopy on <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mi>SrFeO</a:mi><a:mn>3</a:mn></a:msub></a:math> which is one of the classical conducting transition-metal oxides with a noncollinear magnetic structure. The obtained spectra show detailed charge-transfer (CT) satellite structure, Fe <b:math...
We report on our hard x-ray photoemission study of ${\mathrm{Nb}}_{3}{\mathrm{Cl}}_{8}$, wherein the breathing Kagome lattice Nb provides interesting magnetic properties with spin 1/2 per trimer. The $\mathrm{Nb}\phantom{\rule{0.16em}{0ex}}3{d}_{5/2}$ and $3{d}_{3/2}$ core level peaks are accompanied by satellite peaks, suggesting importance $\mathrm{Nb}\phantom{\rule{0.16em}{0ex}}4d$ charge degrees freedom. $\mathrm{Cl}\phantom{\rule{0.16em}{0ex}}1s$ $2p$ spectra have high binding energy...