A5033680836- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Iron-based superconductors research
- X-ray Diffraction in Crystallography
- Rare-earth and actinide compounds
- Topological Materials and Phenomena
- Crystal Structures and Properties
- Glass properties and applications
- Metallic Glasses and Amorphous Alloys
- Neural Networks and Applications
- Machine Learning in Materials Science
- Image Processing and 3D Reconstruction
- Seismic Imaging and Inversion Techniques
- High Entropy Alloys Studies
- Inorganic Fluorides and Related Compounds
- Crystallography and Radiation Phenomena
- Graphene research and applications
- Catalysis and Oxidation Reactions
- High-Temperature Coating Behaviors
- 2D Materials and Applications
- Multiferroics and related materials
- Magnetic properties of thin films
- Seismology and Earthquake Studies
- Nuclear materials and radiation effects
Deutsches Elektronen-Synchrotron DESY
2019-2024
University of Zurich
2016-2024
Politecnico di Milano
2016
Abstract The application of magnetic fields to layered cuprates suppresses their high-temperature superconducting behaviour and reveals competing ground states. In widely studied underdoped YBa 2 Cu 3 O 6+ x (YBCO), the microscopic nature field-induced electronic structural changes at low temperatures remains unclear. Here we report an X-ray study high-field charge density wave (CDW) in YBCO. For hole dopings ∼0.123, find that a field ( B ∼10 T) induces additional CDW correlations along CuO...
We report a temperature dependent x-ray diffraction study of the electronic ordering instabilities in kagome material CsV$_3$Sb$_5$. Our measurements between 10 K and 120 reveal an unexpected reorganization three-dimensional order bulk CsV$_3$Sb$_5$: At K, 2x2x2 superstructure modulation due to is observed, which upon warming changes 2x2x4 at 60 K. The order-order transition discovered here involves change stacking electronically ordered V$_3$Sb$_5$-layers agrees perfectly with anomalies...
The quantum Hall effect (QHE) is traditionally considered a purely two-dimensional (2D) phenomenon. Recently, three-dimensional (3D) version of the QHE has been reported in Dirac semimetal ZrTe5. It was proposed to arise from magnetic-field-driven Fermi surface instability, transforming original 3D electron system into stack 2D sheets. Here, we report thermodynamic, thermoelectric and charge transport measurements on ZrTe5 regime. measured thermodynamic properties: magnetization ultrasound...
In the cuprates, high-temperature superconductivity, spin-density-wave order, and charge-density-wave (CDW) order are intertwined, symmetry determination is challenging due to domain formation. We investigated CDW in prototypical cuprate La_{1.88}Sr_{0.12}CuO_{4} via x-ray diffraction employing uniaxial pressure as a domain-selective stimulus establish unidirectional nature of unambiguously. A fivefold enhancement amplitude found when homogeneous superconductivity partially suppressed by...
Abstract The transition temperature T c of unconventional superconductivity is often tunable. For a monolayer FeSe, for example, the sweet spot uniquely bound to titanium-oxide substrates. By contrast La 2−x Sr x CuO 4 thin films, such substrates are sub-optimal and highest instead obtained using LaSrAlO . An outstanding challenge thus understand optimal conditions in films: which microscopic parameters drive change how can we tune them? Here demonstrate, by combination x-ray absorption...
Abstract A combination of complementary high-energy X-ray diffraction, containerless solidification during electromagnetic levitation and transmission electron microscopy is used to map in situ the phase evolution a prototype Cu-Zr-Al glass flash-annealing imposed at rate ranging from 10 2 3 K s −1 cooling liquid state. Such experimental techniques provides hitherto inaccessible insight into phase-transformation mechanism its kinetics with high temporal resolution over entire temperature...
Interlayer coupling is strongly implicated in the complex electronic properties of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>1</a:mn><a:mi>T</a:mi></a:mrow><a:mo>−</a:mo><a:msub><a:mi>TaS</a:mi><a:mn>2</a:mn></a:msub></a:math>. Uniaxial strain engineering offers a route to modify this order elucidate its interplay with structure and correlations. Here, we employ angle-resolved photoemission spectroscopy (ARPES) reveal effect uniaxial on <b:math...
Abstract Quantum fluctuations in low-dimensional systems and near quantum phase transitions have significant influences on material properties. Yet, it is difficult to experimentally gauge the strength importance of fluctuations. Here we provide a resonant inelastic x-ray scattering study magnon excitations Mott insulating cuprates. From thin film SrCuO 2 , single- bi-magnon dispersions are derived. Using an effective Heisenberg Hamiltonian generated from Hubbard model, show that...
Quantum matter phases may co-exist microscopically even when they display competing tendencies. A fundamental question is whether such a competition can be avoided through the elimination of one phase while other condenses into ground state. Here, we present high-resolution neutron spectroscopy study low-energy spin excitations in high-temperature superconductor La1.855Sr0.145CuO4. In normal state, find magnetic fluctuations at incommensurate reciprocal lattice positions where...
The strongly correlated insulator Ca$_{2}$RuO$_4$ is considered as a paradigmatic realization of both spin-orbital physics and band-Mott insulating phase, characterized by orbitally selective coexistence band Mott gap. We present high-resolution oxygen $K$-edge resonant inelastic X-ray scattering study the antiferromagnetic state Ca$_{2}$RuO$_4$. A set low-energy ($\sim$80 400 meV) high-energy ($\sim$1.3 2.2 eV) excitations are reported that show strong incident light polarization...
Abstract The removal or cancellation of noise has wide-spread applications in imaging and acoustics. In everyday life, such as image restoration, denoising may even include generative aspects, which are unfaithful to the ground truth. For scientific use, however, must reproduce truth accurately. Denoising data is further challenged by unknown profiles. fact, will often from multiple distinct sources, substantially reduces applicability simulation-based approaches. Here we show how can be...
Abstract The kagome lattice is an intriguing and rich platform for discovering, tuning understanding the diverse phases of quantum matter, crucial advancing modern future electronics. Despite considerable efforts, accessing correlated at room temperature has been challenging. Using single-crystal X-ray diffraction, we discovered charge order above in La(Ru 1− x Fe ) 3 Si 2 ( = 0, 0.01, 0.05), where related to out-of-plane Ru atom displacements appears below T CO,I ≃ 400 K. secondary ordered...
We use resonant inelastic x-ray scattering to investigate charge-stripe correlations in La$_{1.675}$Eu$_{0.2}$Sr$_{0.125}$CuO$_4$. By differentiating elastic from scattering, it is demonstrated that precede both the structural low-temperature tetragonal phase and transport-defined pseudogap onset. The peak amplitude charge stripes decays approximately as $T^{-2}$ towards our detection limit. in-plane integrated intensity, however, remains roughly temperature independent. Therefore, although...
Abstract The key to fabricating complex, hierarchical materials is the control of chemical reactions at various length scales. To this end, classical model nucleation and growth fails provide sufficient information. Here, we illustrate how modern X-ray spectroscopic scattering in situ studies bridge molecular- macro- scales for assemblies polyhedrally shaped CoO nanocrystals. Utilizing high energy-resolution fluorescence-detected absorption spectroscopy, directly access molecular level...
We present a combined x-ray and neutron diffraction study of the stripe ordered superconductor \lscox{0.12}. The average crystal structure is consistent with orthorhombic $Bmab$ space group as commonly reported in literature. This however not symmetry compatible second order phase transition into phase, and, we report here numerous Bragg peaks forbidden are observed. have studied analysed these $Bmab$-forbidden reflections. Fitting intensities yields monoclinic lattice distortions that charge order.
A resonant inelastic x-ray scattering study of overdamped spin excitations in slightly underdoped ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4}$ (LSCO) with $x=0.12$ and 0.145 is presented. Three high-symmetry directions have been investigated: (1) the antinodal $(0,0)\ensuremath{\rightarrow}(\frac{1}{2},0)$, (2) nodal $(0,0)\ensuremath{\rightarrow}(\frac{1}{4},\frac{1}{4})$, (3) zone-boundary direction $(\frac{1}{2},0)\ensuremath{\rightarrow}(\frac{1}{4},\frac{1}{4})$...
Abstract Unconventional superconductivity often couples to other electronic orders in a cooperative or competing fashion. Identifying external stimuli that tune between these two limits is of fundamental interest. Here, we show strain perpendicular the copper-oxide planes directly interaction charge stripe order and La 1.88 Sr 0.12 CuO 4 (LSCO). Compressive c -axis pressure amplifies within superconducting state, while having no impact on normal state. By contrast, dramatically diminishes...
The ability to efficiently control charge and spin in the cuprate high-temperature superconductors is crucial for fundamental research underpins technological development. Here, we explore tunability of magnetism, superconductivity, crystal structure stripe phase La[Formula: see text]Ba[Formula: text]CuO[Formula: text], with [Formula: text] = 0.115 0.135, by employing temperature-dependent (down 400 mK) muon-spin rotation AC susceptibility, as well X-ray scattering experiments under...
Phase transitions and symmetry are intimately linked. Melting of ice, for example, restores translation invariance. The mysterious hidden order (HO) phase ${\mathrm{URu}}_{2}{\mathrm{Si}}_{2}$ has, despite relentless research efforts, kept its breaking element intangible. Here, we present a high-resolution x-ray diffraction study the crystal structure as function hydrostatic pressure. Below critical pressure threshold ${p}_{c}\ensuremath{\approx}3$ kbar, no tetragonal lattice is observed...
We present an in situ uniaxial pressure device optimized for small angle x-ray and neutron scattering experiments at low-temperatures high magnetic fields. A stepper motor generates force, which is transmitted to the sample via a rod with integrated transducer that continuously monitors force. The has been designed generate forces up 200 N both compressive tensile configurations, feedback control allows operating system continuous-pressure mode as temperature changed. can be used various...
Understanding the mechanisms driving early stages of oxidation metallic surfaces is fundamental importance in fields such as nanocatalysis, electrochemistry, and nanoelectronics. In this work, ultrathin Co films deposited on Fe(001)-p(1 × 1)O surface have been investigated by means Auger electron spectroscopy, scanning tunneling microscopy, spectroscopy. The initiated homogeneous oxide nucleation over atomically flat terraces, inducing development a smooth wetting layer when islands...
It is currently understood that high temperature superconductivity (SC) in the transition metal $(M)$ substituted iron arsenides $\mathrm{Ba}{({\mathrm{Fe}}_{1\ensuremath{-}x}{M}_{x})}_{2}{\mathrm{As}}_{2}$ promoted by magnetic excitations with wave vectors $(\ensuremath{\pi},0)$ or $(0,\ensuremath{\pi})$. known while a small amount of Co substitution lead to SC, same does not occur for Mn any value $x$. In this work,...
We present a combined growth and transport study of superconducting single-crystalline ${\mathrm{NdO}}_{0.5}{\mathrm{F}}_{0.5}{\mathrm{BiS}}_{2}$. Evidence two-dimensional superconductivity with significant phase fluctuations preformed Cooper pairs preceding the transition is reported. This result based on three key observations. (1) The resistive temperature ${T}_{c}$ (defined by resistivity $\ensuremath{\rho}\ensuremath{\rightarrow}0$) increases increasing disorder. (2) As...