E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[37041, 56733]
Open Access
Abstract: 2D Prussian blue and its analogues hold great promise for applications in catalysis, energy conversion, sensing, and memory devices, thanks to their open frameworks, surface activity, and directional ion transport. However, synthesizing high-quality and large-area 2D films remains a major challenge. Here, we present a robust and scalable liquid-liquid interfacial synthesis that enables the formation of continuous, 2D flakes of Prussian blue (Fe3+[Fe2+(CN)6]0.75) with tunable thicknesses from âŒ2 nm to several hundred nanometers. The controlled reduction of [Fe3+(CN)6]3â to [Fe2+(CN)6]4â enables slow, directed growth of 2D-FeFe layers. Unlike films formed from nanoparticles, this method yields high-quality flakes suitable for integration into devices. As a demonstration, we incorporated these films into Ag filament-based electrochemical metallization memristors. The 2D-FeFe devices â„50 nm thick exhibited reliable bipolar electrical switching, with high Roff/on ratios (âŒ106), >6 h retention, and stability over 150 cycles. Strikingly, switching was observed across 1.5 ”m lateral gaps, far exceeding conventional silver filament formation distances, highlighting the superior ion transport and structural integrity of these 2D frameworks. This scalable approach to 2D Prussian blue, which has the potential to be extended to other related coordination polymers, offers exciting opportunities beyond memristors, enabling integration into technologies where thin-film compatibility, directional ion transport, and high surface activity are critical, such as catalysis, energy storage, and neuromorphic computing.
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Jan 2026
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I09-Surface and Interface Structural Analysis
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Yue
Yu
,
Xu
Zhang
,
Wenjing
Xu
,
Rongkun
Chen
,
Cien
Liu
,
Yiru
Zhao
,
Yushuo
Hu
,
Zhilai
Fang
,
Ning
Jia
,
Xiangyu
Xu
,
Kelvin H. L.
Zhang
Diamond Proposal Number(s):
[37428]
Abstract: GaN-based deep ultraviolet (DUV) optoelectronic devices have garnered considerable attention for applications in sterilization, biological detection, and optical communications. However, the performance of current DUV optoelectronic devices is limited by the insufficient DUV transparency of conventional electrodes. In this work, the epitaxial growth of degenerately Si-doped Ga2O3 films on GaN as a promising DUV transparent electrode is reported. The 0.5% Si doped Ga2O3 (n+-Ga2O3) films exhibit DUV transparency exceeding 85% in the spectral range from 280 to 400 nm wavelength. Such a high DUV transparency is attributed to the ultrawide bandgap of â5.0 eV of the n+-Ga2O3 film induced by the BursteinâMoss effect due to degenerate doping. Moreover, the n+-Ga2O3 film exhibits a very low specific contact resistance of 1.96 Ă 10â4 Ω cm2 to GaN. High-resolution X-ray photoemission spectroscopic (XPS) study reveals that n+-Ga2O3 forms a type-II staggered band alignment with GaN with a low interface barrier of 0.15 eV and a narrow band bending thickness of a few nm. The small barrier, together with the degenerately doped Ga2O3 film, enables excellent electrical contact at the n+-Ga2O3/GaN interface and low contact resistance. This work demonstrates n+-Ga2O3 as a promising alternative for DUV transparent electrode for GaN-based DUV devices.
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Jan 2026
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I05-ARPES
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Diamond Proposal Number(s):
[34246]
Open Access
Abstract: Magnetic van der Waals materials are an important building block to realize spintronic functionalities in heterostructures of two-dimensional (2D) materials. However, establishing their magnetic and electronic properties and the interrelationship between the magnetic ground state and electronic structure is often challenging because only a limited number of techniques can probe magnetism and electronic structure on length scales of tens to hundreds of nanometers. Chromium chalcogenides are a class of 2D magnetic materials for which a rich interplay between structure and magnetism has been predicted. Here, we combine angle-resolved photoemission and quasiparticle interference imaging to establish the electronic structure of a monolayer of CrTe2 on graphite. From a comparison of model calculations with spectroscopic mapping using angle-resolved photoemission spectroscopy and scanning tunneling microscopy we establish the magnetic ground state and the low-energy electronic structure. We demonstrate that the band structure of monolayer CrTe2 is captured well by density functional theory (DFT) in a DFT+đ framework when a Coulomb repulsion of đ=2.5eV is accounted for.
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Dec 2025
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
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Diamond Proposal Number(s):
[33956]
Abstract: Multiwavelength light emission was observed in undoped tin oxide thin films deposited by metal-organic chemical vapor deposition at temperatures ranging from 700°C to 800°C. This work presents the relationship between the presence and nature of defects in undoped SnO2 thin films and their emission properties. Blue and orange emissions were observed on SnO2 thin films using a He-Cd laser and an Xe lamp at an excitation wavelength of 325 nm. Systematic characterization and analysis techniques, including low-temperature photoluminescence at temperatures ranging from 77K to 298K and surface-sensitive techniques using brilliant synchrotron radiation facilities, were applied to elucidate the features and origin of emission in undoped SnO2 layers. Based on our results, surface and bulk oxygen and interstitial tin defects play an important role in multi-wavelength emission processes and can be separately activated by controlling the applied light source.
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Dec 2025
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Open Access
Abstract: Synthetic antiferromagnets consist of two ferromagnetic layers that are antiferromagnetically coupled. These systems support complex dynamical magnetic excitations, where interlayer coupling gives rise to both in-phase (acoustic) and anti-phase (optical) magnonic modes. Typically, simultaneous excitation of both modes requires breaking the symmetry between the ferromagnetic layers â commonly achieved through slight misalignment of the experimental setup or by modifying the intrinsic magnetic properties. In our approach, we utilize a pinned synthetic antiferromagnet, where one of the ferromagnetic layers is exchange-coupled to an antiferromagnet. We demonstrate that by tuning the thickness of the antiferromagnet and slightly enhancing the magnetic anisotropy of the pinned layer, both acoustic and optical modes can be efficiently excited â without the need for experimental misalignment or changes to the intrinsic material properties. Under specific conditions, the magnon dispersion relations exhibit anti-crossing behavior, resulting in the emergence of a magnonic bandgap â a clear signature of strong magnon-magnon coupling. The coupling efficiency
â , defined as the ratio between the bandgap and the characteristic frequency, reaches
â , well in the ultrastrong and approaching the deep-strong coupling regime of
â . The combination of strong mode hybridization, a sizable magnonic bandgap, and high ferromagnetic resonance coherence over large areas â all achieved at room temperature without cryogenic cooling â underscores the potential of these systems for quantum magnonic applications, including quantum computing.
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Dec 2025
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I09-Surface and Interface Structural Analysis
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Abstract: Superconducting microwave circuits are a promising physical implementation of quantum computing. A significant challenge with the development of superconducting qubits is the materials source of loss leading to qubit decoherence. Much of this loss is dielectric loss or quasiparticle dissipation at superconductor surfaces and interfaces. In order to understand the loss mechanisms microscopically, it is necessary to have an accurate picture of the atomic structure and microstructure. In this work, we explore the structure of three interfaces. First, we present non- destructive X-ray characterization of the NbH surface precipitation in Nb thin films. Unwanted hydride precipitation in niobium-based superconducting circuits is a side effect of hydrofluoric acid etching of the Nb surface oxide. The precipitate microstructure is challenging to probe because of the high mobility of hydrogen in niobium. Using X-rays diffraction, we show evidence supporting phase-field simulations that the nucleation of NbH occurs at free surfaces. Using darkfield X-ray nanoprobe microscopy, we identify a complex microstructure suggesting a martensitic nucleation that transitions to a dendritic growth. Next, we present X-ray standing wave excited X-ray photoelectron spectroscopy of the annealed, Nb(110) ordered oxide surface layer. We discover the existence of an oxygen interstitial rich subsurface layer and identify the origin of two distinct oxygen chemical states at the surface: one coming from this subsurface layer, and the other from the surface NbO termination. Last, we present the heteroepitaxy of single crystal Al2O3 with a TiN. We identify TiN as an ideal substrate for the epitaxial growth of Al2O3 in a capacitor geometry based on the high degree of crystallinity and sharp interfaces with minimal diffusion and
3
we measure the two-level-state loss of the Al2O3 junction dielectric layer. We present this interface as an alternative to the commonly used amorphous alumina in Josephson Junctions.
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Dec 2025
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I09-Surface and Interface Structural Analysis
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G.
Cicconi
,
M.
Bosi
,
F.
Mezzadri
,
A.
Ugolotti
,
I.
Cora
,
L.
Seravalli
,
H.
Tornatzky
,
J.
LĂ€hnemann
,
M. R.
Wagner
,
P.
Bhatt
,
P. K.
Thakur
,
T.-L.
Lee
,
A.
Regoutz
,
A.
Baraldi
,
D.
Bersani
,
L.
Cademartiri
,
A.
Parisini
,
B.
PĂ©cz
,
L.
Miglio
,
R.
Fornari
,
P.
Mazzolini
Diamond Proposal Number(s):
[36180]
Open Access
Abstract: The ultra-wide bandgap semiconductor rutile germanium oxide (r-GeO2, Eg â 4.6âŻeV) is gaining momentum in the quest for novel materials for power electronics. In this work, we experimentally and theoretically investigate the physical mechanisms behind the nucleation and growth of epitaxial (001) r-GeO2 on isostructural r-TiO2 substrates via metalorganic vapor phase epitaxy (MOVPE) using isobutylgermane and O2 precursors. In the identified deposition window, the thin film growth seems to be affected by partial GeO suboxide desorption, and we observe that the layers are always composed of r-GeO2 islands embedded and/or surrounded by amorphous material. Ge/Ti interdiffusion at the epilayer-substrate interface is found at the base of each r-GeO2 island; combining experimental analysis and multiscale theoretical simulations we discuss how such a process is fundamental to achieve partial strain mitigation allowing for the nucleation of epitaxial r-GeO2 and suggest in this regard a limiting threshold to avoid the formation of amorphous material. Moreover, we shed light on the formation of different facets in r-GeO2 at early stages of growth and after merging of islands.
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Dec 2025
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DIAD-Dual Imaging and Diffraction Beamline
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Loris
Chavée
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Emile
Haye
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Jochen M.
Schneider
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Stanislav
MrĂĄz
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Andreas
Pflug
,
Dennis
Barton
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Armel
Descamps
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Claudie
Josse
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JĂ©rĂŽme
MĂŒller
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Pavel
Moskovkin
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James
Marrow
,
Amael
Caillard
,
Stephane
Lucas
Diamond Proposal Number(s):
[34010]
Abstract: The deposition of functional coatings on open-cell foam substrates using magnetron
sputtering is gaining popularity, particularly for applications like Oxygen Evolution
Reaction (OER)/Hydrogen Evolution Reaction (HER) catalysis, batteries, and
supercapacitors. While most research focuses on performance, little attention has
been paid to the coating growth mechanisms or properties within the foam, which could
significantly impact device performance. This work investigates the properties and
growth mechanisms of TiOâ coatings inside porous foams, using experimental and
modeling techniques.
The structure, composition and thickness of the coating on the outermost surface of
the foam are studied using Focused Ion Beam (FIB), Scanning Transmission Electron
Microscopy (STEM), Energy-Dispersive X-Ray Spectroscopy (EDS), Selected Area
Electron Diffraction (SAED) and High-Resolution Transmission Electron Microscopy
(HRTEM). The experimental results reveal the formation of a dense, (quasi-
)stoichiometric and crystalline coating.
Numerical simulations and experiments highlight the transport of plasma particles in
the foam. Interestingly, Direct Simulation Monte Carlo (DSMC)/Particle-In-Cell Monte
Carlo (PICMC) models, coupled with Mass-Energy Analyzer (MEA) experiments,
demonstrate that the particle flux is reduced, but the particle energy distribution is not
Accepted Manuscript affected while traveling inside the foam. Using kinetic Monte Carlo (kMC) thin film
growth models provided by Virtual CoaterTM, the physical properties of the coating
inside the foam have been modeled, and the drop in coating thickness as well as the
impact of bias voltage on densification, resistivity, and optical absorption are
confirmed. Synchrotron X-Ray Diffraction (SXRD) analyses of the foam demonstrate
that the same crystalline phase is obtained along the foam thickness, but it can be
tailored with bias voltages. The decrease in the recorded SXRD signal with increasing
depth inside the foam also suggests a drop in coating thickness.
The new insights on the properties of coatings inside open-cell foams presented in this
study can be used to improve future foam-based devices.
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Dec 2025
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I07-Surface & interface diffraction
I15-Extreme Conditions
I19-Small Molecule Single Crystal Diffraction
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Yang
Lu
,
Young-Kwang
Jung
,
Milos
Dubajic
,
Xinjuan
Li
,
Shabnum
Maqbool
,
Qichun
Gu
,
Xinyu
Bai
,
Yorrick
Boeije
,
Xian Wei
Chua
,
Alessandro J.
Mirabelli
,
Taeheon
Kang
,
Lars
Sonneveld
,
Youcheng
Zhang
,
Thomas A.
Selby
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Capucine
Mamak
,
Kan
Tang
,
Zhongzheng
Yu
,
Tianjun
Liu
,
Miguel
Anaya
,
Stephen
Barlow
,
Seth R.
Marder
,
Bruno
Ehrler
,
Caterina
Ducati
,
Richard H.
Friend
,
Samuel D.
Stranks
Diamond Proposal Number(s):
[32266, 38601, 30043, 33123, 36628, 38508]
Abstract: Halide perovskites exhibit superior optoelectronic properties but lack precise thickness and band offset control in heterojunctions, which is critical for modular multilayer architectures such as multiple quantum wells. We demonstrate vapor-phase, layer-by-layer heteroepitaxial growth exemplified by CsPbBr3 deposition on single crystals of PEA2PbBr4 (PEA: 2-phenylethylammonium). Angstrom-level thickness control and subangstrom smooth layers enable quantum-confined photoluminescence of CsPbBr3 from monolayer, bilayer, and through to bulk. The interfacial structure controls the electronic structure from a CsâPEA-terminated interface (type II heterojunction) to a PEAâPEA-terminated interface (type I heterojunction), with a layer-tunable band offset shift exceeding 0.5 electron volts. Electron transfer from CsPbBr3 to PEA2PbBr4 for a type II CsâPEA heterojunction results in delayed electron-hole recombination beyond 10 microseconds. Precise quantum confinement control and large band offset tunability unlock perovskite heterojunctions as platforms for scalable, superlattice-based optoelectronic applications.
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Nov 2025
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I06-Nanoscience (XPEEM)
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Lingzhi
Wen
,
Cong
Li
,
Guanshihan
Du
,
Sijie
Wu
,
Jianbing
Zhang
,
Xiaoyin
Pan
,
Clodomiro
Cafolla
,
Lizhe
Hu
,
Yongjun
Wu
,
Zijian
Hong
,
Qing
He
,
Pu
Yu
Diamond Proposal Number(s):
[42042, 36503, 34602, 26142, 22361, 38419]
Abstract: Topological polar textures have garnered significant attention for next-generation electronic devices due to associated emergent functionalities (e.g., chirality, enhanced conductivity, and negative capacitance). Most studies stabilize topological textures using depolarization field in ferroelectric- dielectric superlattices or heterostructures; however, the lack of direct electrical contacts dramatically hinders the corresponding field-driven control and applications. Here, the formation of electric-field-switchable NĂ©el-type polar skyrmions at room temperature is demonstrated in Ba0.8Sr0.2TiO3 (BSTO) thin films directly grown on metallic SrRuO3 electrodes. In this study, strategic Sr substitution is employed to engineer the Landau energy landscape of ferroelectric material BaTiO3, which eventually facilitates the coexistence of multiple polarization states without sacrificing room-temperature ferroelectricity. Piezoelectric force microscopy (PFM) uncovers a critical BSTO thickness to host the phenomena: conventional ferroelectric domains dominate 60-nm thick BSTO, whereas high-density topological polar textures emerge in 10-nm thick BSTO. Specifically, vector-PFM analysis identifies two stable skyrmion states in 10-nm BSTO with convergent- and divergent- in-plane polarization components. Importantly, an electric-field-driven interconversion between these topological states is demonstrated by reconfiguring the free-energy landscape, which is also supported by the phase-field simulations. This work provides a direct pathway of using metallic electrodes for the dynamic control of topological ferroelectrics in functional devices.
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Nov 2025
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