Category: SOLARIS

A breakthrough cyanide-bridged molecular magnet

A breakthrough cyanide-bridged molecular magnet

Researchers at the Jagiellonian University have developed a new Prussian Blue analogue that exhibits ferrimagnetic ordering at a record-high temperature exceeding 400 K (127 °C). The discovery, reported in the Advanced Science article “Heavy Prussian Blue Analog with Magnetic Ordering above 400 K”, concerns a cyanide-bridged molecular magnet composed of vanadium(II) and molybdenum(III) ions, which replace the traditional iron ions found in the Prussian Blue structure. The experimental work described in the publication was carried out at SOLARIS on the ASTRA beamline.

The study reports the synthesis, structural analysis and magnetic characterisation of the amorphous compound {[K(crypt222)]0.34VII1.37MoIII(CN)6(BF4)0.08·xCH3CN} n(VII–MoIII(CN)6), demonstrating its ferrimagnetic behaviour up to 400 K (127 °C) – a temperature range previously inaccessible for conventional cyanide–bridged magnets.

Read more on the SOLARIS website

Image: A single frame from the video illustrating the behaviour of VII–CrIII(CN)6 in a varying magnetic field between 0 and 0.5 T.

From superconductor to magnetic frustration and Fermi surface reconstruction

From superconductor to magnetic frustration and Fermi surface reconstruction

A collaborative team from MagTop, the Institute of Physics PAS in Warsaw and the URANOS beamline researchers at the SOLARIS Synchrotron, has unveiled an unexpected transformation in the 2D quantum material NbSe2. The article published in Physical Review B, titled ‘Magnetic frustration enforced electronic reconstruction in Ni-intercalated NbSe2: Suppression of electronic orders’ demonstrates that introducing nickel atoms into the crystal, forces electronic reconstruction, eliminating its characteristic such as superconductivity and charge ordering due to magnetic frustration.

Niobium diselenide (NbSe2) is a well-known 2D layered crystal where electrons organize themselves in remarkable ways, it exhibits non-magnetic ground state. Around 30 K, the electrons form a charge-density wave; a periodic ripple in their density and at 7 K, electrons combine into pairs and the material becomes superconducting, carrying electric current without resistance. These two electronic orders coexist naturally and make NbSe2 a model system for studying complex quantum behaviour.

In the article, researchers explored what happens when nickel atoms are inserted between the layers of NbSe2 i.e. Ni0.19NbSe2. This particular, intermediate concentration of Ni, was chosen to introduce moderate disorder into the studied system. Instead of simply disturbing the structure, the added nickel fundamentally changes how electrons move and interact. Both superconductivity and the charge-density wave disappear, and the material begins to behave like a frustrated magnet. Measurements show that the intercalated nickel atoms introduce magnetic moments that interact with each other in conflicting ways. As the sample is cooled, these moments attempt to align in opposite directions, but cannot settle into a single, well-ordered pattern. This “magnetic frustration” is a hallmark of systems where competing interactions prevent the formation of a simple magnetic state.

Read more on the SOLARIS website

Image: Fermi surface maps at 84 K of pristine NbSe2 and Niinterncalated NbSe2 measured using ARPES. (a), (b) Comparison of the Fermi surfaces for pristine NbSe2 and Ni0.19NbSe2 resp. obtained from the sum of intensities of horizontal and vertical linear polarizations. The Ni-intercalated sample shows clear Fermi surface reconstruction, indicated by red arrows. (c), (d) Fermi surface maps of NbSe2 and Ni0.19NbSe2 obtained from the sum of intensities of left- and right-circular polarizations, further highlighting modifications in the electronic structure due to Ni intercalation (red arrows).

A new series of [M(B11H11)2] 3-anions with metals in their highest known oxidation states

A new series of [M(B11H11)2] 3-anions with metals in their highest known oxidation states

In collaboration with Prof. Finze’s research group (University of Würzburg) and Dr. Alexey Maximenko (SOLARIS National Synchrotron Radiation Centre at Jagiellonian University) Prof. Adam Slabon’s research group has successfully synthesized and comprehensively characterized a new series of anions of the type [M(B11H11)2]3- (M = Cu, Ag, Au). The nido-[B11H11]4- ligand coordinates to copper, silver, and gold stabilizing them in the exceptionally high formal oxidation state +V. This is the highest oxidation state known to date for these metals. XANES analysis, carried out by Dr. Alexey Maximenko, additionally confirmed the unusually high oxidation state of copper in K3[Cu(B11H11)2]·5H2O.

DFT calculations showed the relative stability of different structural isomers, while experimental investigations revealed an unusual property of the silver complex. X-ray structural analyses of single crystals revealed that [Ag(B11H11)2]3⁻exists in equilibrium between two coordination forms: a kinetically stable η5 species with Ag(V) and a labile η2species with Ag(I). When cooled below 130 K, a reversible phase transition occurs in which the ligand coordination changes from η5 na η2 and reverts back when heated. This is the first observation of such low-temperature isomerization in this class of compounds.

Read more on the SOLARIS website

Image: Reversible transition between (n-Bu4N)3[Ag+V(η5 – B11H11)2] and (n-Bu4N)3[Ag+I (η2-B11H11)2]

LEAPS chairmanship transferred to Thomas Feurer

LEAPS chairmanship transferred to Thomas Feurer

Consortium set to increase influence in Brussels and broaden funding base

At the 8th LEAPS Plenary Meeting, Prof. Thomas Feurer was welcomed as the 2026 Chair of the League of European Accelerator-based Photon Sources. Feurer is also Chairman of the Management Board of European XFEL and succeeds Prof. Jakub Szlachetko from the National Synchrotron Radiation Centre SOLARIS in Krakow, Poland. 

“It is an honour to be chairing LEAPS,” said Feurer, who attended the meeting remotely. “I am looking forward to continuing the excellent work that has been done here in recent years.” A significant milestone for LEAPS under Feurer’s leadership will be its registration as an international non-profit association under Belgian law in spring 2026. “This will result in stronger visibility and influence in Brussels and beyond, enhancing our ability to form cross-sectoral partnerships in Europe”, Feurer explained.

As a non-profit entity, LEAPS will facilitate collaboration agreements in science and technology between its members and help coordinate funding. Feurer is looking to broaden the funding base for European photon science by pursuing multi-partner opportunities, including partnerships with industry consortia. While building an increased presence at EU level, he also intends to align LEAPS more closely with national roadmaps.

The LEAPS chairmanship was ceremonially handed over at the consortium meeting. Prof. Serguei Molodtsov, Scientific Director of European XFEL, accepted the symbolic baton on Thomas Feurer’s behalf. 

Read more on the European XFEL website

Image: Prof. Serguei Molodtsov, Scientific Director of European XFEL, accepts the symbolic chairmanship baton on Thomas Feurer’s behalf

Credit: Joanna Kowalik

The role of glycosaminoglycans in enhancing protein citrullination in rheumatoid arthritis

The role of glycosaminoglycans in enhancing protein citrullination in rheumatoid arthritis

A group of scientists led by Dr. Tomasz Kantyka from the Małopolska Center for Biotechnology at the Jagiellonian University, in collaboration with the Department of Microbiology at the Jagiellonian University, the University of Bergen, and the SOLARIS Center, is conducting research on the molecular mechanisms associated with rheumatoid arthritis (RA). This disease is an autoimmune disorder in which the immune system mistakenly attacks its own cells, leading to chronic inflammation and joint damage.

One of the characteristic features of RA is the presence of antibodies that recognize proteins containing citrulline, a modified form of the amino acid – arginine. The process of citrulline formation is influenced by the enzyme peptidyl arginine deiminase 4 (PAD4). Scientists are trying to investigate what causes the excessive activity of this enzyme and what environmental factors may promote the formation of citrullinated proteins, which then become targets for the immune system.

In the latest study, the team discovered that glycosaminoglycans—sugar-like molecules naturally found in the extracellular matrix of tissues, such as heparin, heparan sulfate, and chondroitin sulfate—can increase the activity of the PAD4 enzyme. Typically, this enzyme requires high calcium concentrations to function effectively. However, calcium levels in cells and tissues are too low to activate PAD4 on their own. The researchers showed that glycosaminoglycans can “help” the enzyme function even at physiological calcium levels.

Read more on the SOLARIS website

Image: PAD4 mechanism of action in rheumatoidal arthtitis (RA). PAD4 is responsible for citrulination of proteins. Interaction with glycosaminoglycans increases the citrulination level by increase calcium ions recruitment. This can lead to autoimmune degradation od health joint tissue.

Zinc redistribution within the plant root system as a mechanism of adaptation

Zinc redistribution within the plant root system as a mechanism of adaptation

Researchers from the Faculty of Biology, University of Warsaw, grew tobacco plants in a transparent soil system that mimics natural conditions, allowing for a controlled heterogeneous distribution of nutrients. They discovered that when some parts of the roots had access to Zn while others did not, the Zn‑deficient roots did not show the usual Zn deficiency response. This suggested a previously unknown distribution of Zn within the root system, from “Zn‑sufficient” roots to “Zn‑deficient” ones.

To confirm that Zn was redistributed within the plant body, a collaboration with the POLYX beamline team was established to use micro X‑ray fluorescence (μXRF) imaging at the Polish National Synchrotron Radiation Center SOLARIS. This state of the art technique enabled them to visualize Zn distribution at high resolution directly in plant tissues. The analyses revealed that under uneven Zn conditions, the element accumulated evenly in the root system but, surprisingly, there was a preferential accumulation of Zn in the leaf veins, providing new insight into potential Zn distribution routes. The researchers also linked these physiological changes to the activity of key Zn transports, such as NtZIP4B (a Zn importer), NtHMA4a/b (Zn exporters), and NtNAS (a Zn chelator). Interestingly, the position of Zn in the soil—whether in upper or lower layers—affected how strongly genes coding these transporters were expressed and how much Zn reached the leaves.

Read more on the SOLARIS website

Image: The figure shows series of experiments about plants coping with uneven access to zinc in the soil. Using an innovative “transparent soil” system and micro‑XRF at SOLARIS, scientists from the University of Warsaw observed how roots transport zinc from zones with sufficient supply to zinc‑deficient parts of the root system, ensuring stable plant growth. This discovery opens new perspectives for sustainable fertilization and improving crop quality.

Iron under the ARPES Lens: how spin and magnetism shape the metal’s surface state

Iron under the ARPES Lens: how spin and magnetism shape the metal’s surface state

Researchers from the Jerzy Haber Institute of Catalysis and Surface Chemistry of the Polish Academy of Sciences in Kraków have carried out advanced experiments using angle-resolved photoemission spectroscopy (ARPES). They discovered a new surface state of iron Fe(001), whose symmetry changes depending on the magnetization direction of the layer. The results of their study have been published in the prestigious New Journal of Physics.

The electronic band structure of iron has been investigated for decades, but earlier studies were limited by experimental constraints. Today, with access to high-resolution ARPES facilities, such as the Phelix beamline at the Solaris synchrotron in Kraków, scientists can explore the electronic states of materials with unprecedented precision.

For the first time, the existence of a surface state on Fe(001) was unambiguously demonstrated in the epitaxial Fe/Au(001) system. Moreover, the Kraków team was the first to map this state across the full range of energy and momentum. Previous experiments, for example on Fe(001)/W(001), had been restricted to only a few high-symmetry directions or normal emission. By examining the surface state throughout the Brillouin zone, the researchers identified specific regions where spin–orbit coupling modifies the surface electronic states depending on the magnetization direction.

Read more on the SOLARIS website

Image: Surface state of Fe(001)/Au(001) within entire Brillouin zone and Rashba effect at the zone boudary

Thyroid gland as one of the important reservoirs of microplastics in the human body

Thyroid gland as one of the important reservoirs of microplastics in the human body

A research team from Lublin under the scientific supervision of Prof. Jolanta Flieger conducted groundbreaking studies on the distribution of micro- and nanoplastics (MP, NP) in the human body, utilising advanced spectroscopic and microscopic techniques at the SOLARIS. Post-mortem tissue samples were analysed, revealing uneven translocation of MP and a particular affinity of the thyroid gland for their accumulation (40.4 MP/g). The findings suggest a potential link between the presence of MP in the thyroid and the increasing incidence of endocrine disorders and head and neck cancers.

The problem of environmental pollution with microplastics (MP) is growing. Currently, it is difficult to avoid contact with products made of polymeric materials [1]. The latest studies confirm the possibility of MP entering the human body through the digestive tract, respiratory tract or skin and translocation to various organs [2]. MP toxicity is associated with the release of hazardous substances into the body based on the “Trojan horse effect” and with the small size of MP [3]. To date, studies on the health effects of MP accumulation are conducted in vitro on cell lines or in vivo on animal models, which do not reflect the conditions of chronic accumulation to which humans are exposed [4]. In turn, population studies on humans examine MP accumulation in selected organs [5]. Less attention is paid to the accumulation of nanoplastics (NP) and natural polymers. The study of MP in tissues also encounters many methodological problems. References: In the study on several tissues collected post mortem from one patient, a new trend of research on the distribution of MPs in the body was initiated in order to identify organs that preferentially accumulate foreign particles. The tissues were digested and filtered. Both the material collected on the filter and the filtrates were examined to find particles of micro- and nano-size (<20 nm). Techniques dedicated to the identification of polymers were used; MALDI-TOF MS, optical microscopy, SEM-EDS and the rarely used O-PTIR microscope technology. O-PTIR infrared measurements with sub-micron spatial resolution confirmed the presence of micro- and nanoparticles and were used to identify the polymers.

Read more on the SOLARIS website

Image: Experiments underway on the CIRI beamline at SOLARIS

Credit: SOLARIS

Universal vaccine of the future

Universal vaccine of the future

Researchers from the Małopolska Centre of Biotechnology have developed an innovative, modular nanoparticle that could become the foundation of a universal vaccine. By using a phage capsid and antigens derived from the SARS-CoV-2 virus, along with immune response-enhancing elements, the new technology allows for rapid adaptation of the vaccine to emerging pathogens. The structural part of the project was carried out at the Cryo-Electron Microscopy Laboratory at the National Synchrotron Radiation Centre SOLARIS.

Researchers have developed a nanoparticle is based on a phage capsid that has been devoid of its own genetic material and instead equipped with antigens derived from the SARS-CoV-2 virus: specifically, the RBD (Receptor Binding Domain) protein. The research team, led by Dr. Antonina Naskalska, enhanced the nanoparticles with elements that could potentially boost the immune response: short, single-stranded DNA fragments or longer, coding mRNA sequences. The nanoparticle was designed in a modular fashion, allowing for the replacement of antigens displayed on its surface or molecules packed inside the capsid. The advantage of such a vaccine design lies in its ability to be rapidly adapted to an emerging pathogen or a new virus variant.


One of the key aspects of the presented vaccine prototype is the trimeric form of the RBD protein—identical to the form found in the SARS-CoV-2 virus. An organism vaccinated with such an antigen has a greater chance of producing effective antibodies that, in the event of exposure to the virus, will protect it from infection. Demonstrating the trimeric form of the RBD antigen on the surface of the presented nanoparticles was made possible through structural studies using cryogenic electron microscopy (cryo-EM), conducted at the National Synchrotron Radiation Centre SOLARIS.

Read more on SOLARIS website

Studying tRNAs by cryo-EM, biophysics, and computational modeling

Studying tRNAs by cryo-EM, biophysics, and computational modeling

In a pioneering study entitled “Determining the effects of pseudouridine incorporation on human tRNAs” published in EMBO Journal (Link 1), researchers from Malopolska Centre of Biotechnology (Link2) of the Jagiellonian University in Krakow (Link 3), in collaboration with scientists from the International Institute of Molecular and Cell Biology (IIMCB) in Warsaw (Link 4) and institutions from the United Kingdom and France, have significantly advanced our understanding of how specific modifications in transfer RNAs (tRNAs) affect their structure and stability.

tRNAs are essential molecules decoding genetic information into proteins, fundamental to all living organisms. We know tRNAs as long as we know DNA, but historically structural studies of tRNAs have been challenging due to their small size and complexity. The published work shows the structure of four human tRNAs before and after the enzyme-mediated introduction of pseudouridine (Ψ), linking these modifications to enhanced stability and certain structural changes. The findings reveal that the incorporation of Ψ, which is also incorporated in recent mRNA vaccines, not only stabilizes tRNAs, but also induces significant local structural changes. In detail, interactions between the D- and T-arms of the tRNA were identified as critical for maintaining their overall tertiary structure.

“This study demonstrates the profound impact of RNA modifications on tRNA stability and function,” said prof. Sebastian Glatt (Link 5), the leader of this study. “Our findings not only enhance our understanding of tRNA biogenesis but also highlight the potential applications of engineered tRNAs for therapeutic purposes.” adds Anna Biela, the first author of the work.

Key results from the study include:

• The first cryo-EM structures of multiple unmodified and pseudouridylated human tRNAs.

• Clear evidence that specific pseudouridine modifications significantly increase the stability of tRNAs.

• Context-dependent impact of modifications, indicating that not all pseudouridine modifications are equally beneficial.

The study was possible owing to the interdisciplinary combination of experimental and computational analyses. It utilized the advanced single-particle cryo-electron microscopy (cryo-EM) infrastructure at the Solaris Synchrotron in Krakow (Link 6), the Structural Biology Core Fcaility (SBCF, Link 7) at MCB, novel biophysical techniques developed by Jakub Novak, and computational modeling and simulations.

Read more on SOLARIS website

Caught in the frame: the birth of nanostructures

Caught in the frame: the birth of nanostructures

A team led by prof. Magdalena Parlińska-Wojtan from the Institute of Nuclear Physics of the Polish Academy of Sciences conducted advanced research on the process of electrodeposition of metallic nanostructures, using unique microscopic techniques in a liquid environment. International cooperation, including the Silesian University of Technology, the University of Warsaw, the SOLARIS Center, ETH Zurich, and the Fritz Haber Institute in Berlin, resulted in a publication in the prestigious journal Nano Letters.

Modern microscopes and a special electrochemical flow cell allowed scientists from the IFJ PAN to observe the process of creating metal nanoparticles with unprecedented precision. This is a step towards better design of future materials – from fuel cells to advanced sensors. 

Electrodeposition is the process of depositing a metal layer on the surface of an electrode immersed in an electrolyte under the influence of voltage. Although known for a long time, until now it has been difficult to observe its course in detail in real time. Thanks to a special flow cell, in which a microscopic volume is separated by two very thin membranes (and one of them is additionally equipped with electrodes), it became possible to track the formation of a platinum-nickel (PtNi) nanolayer. 

The experiment recorded two mechanisms: direct growth of the PtNi layer on the electrode and the formation of nanoparticles in solution and their deposition on the electrode surface, especially where the electron beam reached. More detailed observations showed that the nanostructures have a spherical shape and a dendritic surface. 
In the next stage of the experiment, carried out in cooperation with the Fritz Haber Institute (Max Planck Gesellschaft), the reaction parameters were modified, which allowed for the recording of nucleation and the growth and dissolution cycles of nanoparticles. Observations showed that the growth rate prevailed over dissolution, thanks to which a durable layer was created. 

Further studies were conducted in the STXM microscope at the SOLARIS center in Krakow. Although the resolution of STXM is lower than TEM, the STXM microscope allows for more precise chemical analysis. It was determined that the PtNi layer consists of metallic platinum and nickel(II) oxide. 

The research opens up new possibilities for controlled synthesis of nanostructures that can be used in energy, electronics and medicine. The recognition of the importance of the work was the inclusion of a graphic from the publication on the cover of the 40th issue of Nano Letters.

Read more on SOLARIS website

Structure of next-generation catalysts

Structure of next-generation catalysts

In a study published in Molecular Catalysis researchers from West Pomeranian University of Technology in Szczecin, Warsaw University of Technology, Graz University of Technology, and National Synchrotron Radiation Centre SOLARIS explored the structure of next-generation catalysts for ammonia synthesis. Only the combination of standard laboratory measurements with possibilities of synchrotron XANES/EXAFS allowed understanding mechanisms leading to the active form of the synthesised material.

To meet the demand from agriculture, the ammonia industry consumes ca. 2% of world energy production, which is a consequence of the high temperature (400-500°C) and high pressure (10-30 MPa) required for the Haber-Bosch process ongoing on widely used iron-based catalysts. The development of new-generation catalysts is essential to lower the operating costs and reduce the CO2 emission of this process. Ammonia is also positioned as a potential form of synthetic fuel of the future. As a result, research and development initiatives focusing on the production of so-called green ammonia, which is produced using hydrogen from water electrolysis powered by renewable energy sources, are gaining momentum.


Development of the new catalyst is high-throughput work, based on screening tests, which allow for the selection of e.g. the optimal carrier, deposition method of the active phase, and load of the active phase. After several dozens of tests, we have designed a promising new catalyst, obtained by impregnation of the γ-Al2O3 with the cobalt and molybdenum compounds, followed by the activation process. The catalytic activity and stability of the obtained catalysts, tested in a laboratory fixed bed reactor under atmospheric pressure at 500 °C, were promising compared to the reference state-of-art Co3Mo3N and the commercial iron-based catalyst. However, the determination of the active phase structure, necessary to fully understand the nature of the catalyst, with standard laboratory methods was ambiguous. Thus, selected obtained catalysts were examined with the help of powerful synchrotron XANES/EXAFS measurements at the ASTRA beamline. 

Read more on SOLARIS website

Image: Scheme of the catalyst synthesis protocol including wet impregnation of support and activation of precursor in ammonia, resulting in highly active and stable catalyst.

Advancing Polarization-Sensitive Photodetection: The Potential of Naturally Anisotropic Tin Monochalcogenides

Advancing Polarization-Sensitive Photodetection: The Potential of Naturally Anisotropic Tin Monochalcogenides

A team of scientists from Wrocław University of Science and Technology, in cooperation with researchers from the URANOS beamline, conducted a series of experiments on layered semiconductors SnS and SnSe using photoemission spectroscopy. Their investigation revealed characteristic features of the electronic band structure, which influence the optical properties of these materials and their potential for near-infrared polarization-sensitive photodetectors.

Polarization-sensitive photodetectors play a crucial role in detecting changes in light polarization, which has applications ranging from liquid crystal technology to biological studies. Existing designs rely on complex optical components, but this study demonstrates that the natural anisotropy of tin monochalcogenides can significantly simplify device construction. This could lead to more efficient and compact photodetectors with polarization resolution.

The unique properties of SnS and SnSe stem from their distorted orthorhombic crystal structure, which introduces directionality in electronic band dispersion. This, in turn, affects their optical characteristics, enabling selective absorption of polarized light. The study also highlights the impact of lone electron pairs on the energy levels of these materials (determining parameters such as work function and ionization potential), which is crucial for the design of heterostructures and metal contacts. Compared to black phosphorus (BP), another anisotropic vdW crystal, SnS and SnSe offer superior stability in ambient conditions, making them more practical for real-world applications.


Read more on SOLARIS website

Dynamic protein nanotubes for advanced applications

Dynamic protein nanotubes for advanced applications

A collaborative research team from Jagiellonian University in Poland and the universities of Leeds, York, and Durham in the UK have made a significant nanotech breakthrough by developing dynamic, pentamer-based protein nanotubes. The study, published in ACS Nano, reveals how an engineered enzyme can assemble into various hollow spherical and cylindrical structures in response to stimuli.

By leveraging the power of electron microscopy and mathematical modeling, the research led by the Azuma group at Malopolska Centre of Biotechnology (MCB) JU has unlocked the ability of a modified enzyme, called lumazine synthase, to form versatile and adaptive nanostructures. The protein shows an extraordinary capacity to morph between hollow spherical shapes and elongated, fiber-like nanotubes, all in response to salt contents in solution. Unlike conventional nanotubes that rely on hexameric or other subunit arrangements, these newly discovered assemblies consist entirely of pentamers. 
Thanks to the state-of-the-art Titan Krios G3i cryo-electron microscope, housed at the National Synchrotron Radiation Centre SOLARIS JU and the Polish high-performance computing infrastructure PLGrid (HPC Centers: ACK Cyfronet AGH), scientists have mapped the structures of these innovative nanocage complexes with remarkable precision.

This pioneering research provides invaluable insights into the molecular mechanics and geometric principles of protein assembly. The findings offer a fresh blueprint for designing nanoarchitectures with customizable shapes and functions, potentially revolutionizing fields such as drug delivery, catalysis, and the creation of advanced nanomaterials.

This discovery is thrilling, as it allows us to see and comprehend the various ways pentamers bind within these nanocages – says Dr. Łukasz Koziej, a leading researcher of the study.
Dr. Yusuke Azuma adds, This work is a promising step forward to pave the way for developing new biomimetic devices and materials with bespoke properties, marking a significant advancement in the field of nanotechnology.

Read more on SOLARIS website


Image: Electron microscopic structures of ball- and tube-shaped assemblies made from an engineered enzyme, lumazine synthase. Unlike many other cases found before, these structures are built entirely with pentameric (pentagonal) units. By simply changing the amount of salt in the solution, they can switch between forming balls or tubes.

Cu2Ge: A New 2D Topological Semimetal

Cu2Ge: A New 2D Topological Semimetal

Members of the “Spectroscopy of Novel Quantum States” team from the Paris Institute of Nanosciences, Sorbonne University, came to the URANOS beamline (synchrotron Solaris) to study the electronic properties of a recently synthetized material: Cu2Ge which is a so-called “nodal line” topological semi-metal. More generally, their scientific objectives are focused on understanding the electronic and magnetic properties of low-dimensional systems such as superconductors, topological and magnetic materials, or Mott insulators.

Among various metal/semiconductor systems, copper/germanium alloys have been studied since the 1990s to understand the formation mechanisms of Schottky barriers, fundamental to diodes of the same name. This Cu2Ge system has attracted renewed interest due to recent predictions of density functional theory (DFT) calculations. Indeed, these calculations predict that the 2D alloy Cu2Ge has a band structure with a 1D intersection of valence and conduction bands, characteristic of a topological semimetal with a Dirac nodal line. In this work, we have experimentally demonstrated for the first time that it is possible to synthesize Cu2Ge on a surface of a copper crystal and that its electronic structure exhibits the expected characteristics of the purely 2D case. Its properties make this alloy a promising candidate for high-frequency electronic applications and an ideal system for studying exotic properties that can emerge in nodal line materials.
Two-dimensional materials are widely studied for their exceptional properties, which allow for potential applications in various fields such as photovoltaics, catalysis, microelectronics, and biomedicine. Additionally, some of these 2D systems exhibit topological properties, further increasing the possibility of discovering new electronic behaviors without a bulk equivalent. Such is the case for Cu2Ge, an alloy consisting of an atomic plane of copper and germanium. Although Cu/Ge alloys were studied several decades ago for Schottky barrier formation, more recent DFT calculations shed new light on these systems. They reveal that, in the case of a 2D Cu2Ge layer, the band structure should exhibit cones intersecting along two closed loops. These “loops” are known as Dirac lines. When these lines are close to the Fermi level, the material noteworthy properties: the potential for higher carrier densities than graphene while maintaining very high carrier velocity.

Read more on SOLARIS website

Perovskite phase symmetry influence the cobalt modifier position

Perovskite phase symmetry influence the cobalt modifier position

A research group from the AGH University of Krakow, specializing in material chemistry, in collaboration with the SOLARIS Center, has published findings on the impact of phase symmetry in the CaTiO3 – SrTiO3 perovskite system on the incorporation of cobalt into the perovskite structure. These cobalt-modified materials are promising for applications in energy conversion technologies and environmental catalysis. The findings, published in Materials Chemistry and Physics, revealed distinct behaviors between calcium-rich (Ca-rich) and strontium-rich (Sr-rich) perovskite materials. The study also examined the impact of non-stoichiometry on both, the position occupied by cobalt in the structure and its oxidation state. A comprehensive understanding of the structural changes in the system was achieved through an innovative approach combining X-ray absorption spectroscopy (XAS) analysis, conducted at the ASTRA beamline, with results from temperature-programmed reduction (TPR) studies.

Ca-rich materials, characterized by orthorhombic symmetry, more effectively incorporate cobalt into the perovskite structure but also tend to form a secondary phase – CoTiO3. In contrast, Sr-rich materials with tetragonal symmetry predominantly lead to the formation of cobalt oxides, particularly Co3O4. The  slight deviations from stoichiometry (a deficiency of atoms in the Ca/Sr sublattice) intensify these effects: in Ca-rich materials, they increase the proportion of the CoTiO3 phase in the system, while in Sr-rich materials, they result in a higher content of cobalt oxides. Additionally, XAS and TPR results revealed that Ca-rich materials contain more cobalt in the +II oxidation state, while Sr-rich materials contain more cobalt in the +III oxidation state.

These findings open new possibilities for designing materials and optimizing their properties for potential applications in catalysis and electrochemical devices. At the same time, they significantly enhance the understanding of solid-state chemistry, particularly the chemistry of materials with a perovskite-type structure.

Read more on SOLARIS website