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Understanding the degree to which charge-stripe, spin-stripe, and superconducting orders compete/coexist is paramount for elucidating the microscopic pairing mechanism in the cuprate high-temperature superconductors. We explore the tunability of magnetism, superconductivity, and crystal structure in the stripe phase of the cuprate La_2−xBa_xCuO₄, by employing complementary techniques under compressive uniaxial stress in the CuO₂ plane. Our results show a sixfold increase ...

The European aviation sector stands at a pivotal juncture in its quest to achieve net-zero climate impacts. Focusing on flight CO₂ emissions overlooks up to 80% of the sector's climate repercussions.

Our research delves deep into the role of electricity-based synthetic jet fuels and direct air carbon capture and storage (DACCS) as potential game-changers. These solutions promise climate-neutral aviation, but there's a catch: the relentless rise in air traffic. Relying solely on renewables-derived synthetic fuels may strain both economic and natural resources. On the flip side, offsetting fossil jet fuel impacts via DACCS poses its own set of challenges. Our findings underscore one clear message: for a genuinely climate-neutral European aviation, we must reconsider the scale of air traffic.

The triangular lattice antiferromagnet (TLAF) has been the standard paradigm of frustrated magnetism for several decades. The most common magnetic ordering in insulating TLAFs is the 120° structure. However, a new triple-Q chiral ordering can emerge in metallic TLAFs, representing the short wave- length limit of magnetic skyrmion crystals. We report the metallic TLAF Co_1/3TaS2 as the first example of tetrahedral triple-Q magnetic ordering with the associated topological Hall effect (non-zero σ_xy(H = 0)). We also ...

The topology of electronic and phonon band structures of graphene is well studied and known to exhibit a Dirac cone at the K point of the Brillouin zone. Here, we applied inelastic x-ray scattering (IXS) along with ab initio calculations to investigate phonon topology in graphite, the 3D analog of graphene. We identified a pair of modes that form a very weakly gapped linear anticrossing at the K point that can be essentially viewed as a Dirac cone approximant. The IXS intensity ...

Magnetic skyrmions, with their distinctive vortex-like magnetic spin configurations, continue to intrigue researchers due to their potential applications in nanoscience and technology. Traditionally skyrmions form two-dimensional hexagonal close-packed lattices, with the skyrmions themselves displaying one of just two types of internal magnetization texture known as Bloch- or Néel-type. Recent theories hinted at the prospect of reconfigurable transitions between skyrmion phases of different lattice types and internal textures. Until now, experimental evidence supporting such theories has been scarce.

We report on measurements of the in-plane magnetic penetration depth (λab) in single crystals of Sr₂RuO₄ down to ≃0.015  K by means of muon-spin rotation-relaxation. The linear temperature dependence of λ⁻²_ab for T≲0.7  K suggests the presence of nodes in the superconducting gap. This statement is further substantiated by observation of the Volovik effect, i.e., the reduction of λ⁻²_ab as a function of the applied magnetic field. The experimental zero-field ...

Strontium titanate is a wide band gap semiconductor. Its surface can be rendered conductive by a mild annealing in vacuum. The present study reveals that by deposition of less than a monolayer of non-volatile organic molecules such as tetracyanoquinodimethane (TCNQ) this conductivity can be completely turned off. In view of the small size of TCNQ (ca. 1 nm) this could allow new pathways toward oxide-based electronics.

Charge ordered kagome lattices have been demonstrated to be intriguing platforms for studying the intertwining of topology, correlation, and magnetism. The recently discovered charge ordered kagome material ScV₆Sn₆ does not feature a magnetic groundstate or excitations, thus it is often regarded as a conventional paramagnet. Here, using advanced muon-spin rotation spectroscopy, we uncover an unexpected hidden magnetism of the charge order. We observe an enhancement ...

In-situ Selective Laser Heat treatment is applied to induce martensite decomposition in Ti-6Al-4V

Excitons coupling to octahedral tilts in Pb nano-perovskites

Crystal field rules heavy fermion delocalization

“Li-rich Ni-rich” core-shell particles are engineered as layered cathode materials for high energy Li-Ion batteries, including a controllable outer "Li-rich Mn-rich" shell improving cyclability.

Kondo impurities provide a nontrivial probe to unravel the character of the excitations of a quantum spin liquid. In the S = 1/2 Kitaev model on the honeycomb lattice, Kondo impurities embedded in the spin-liquid host can be screened by itinerant Majorana fermions via gauge-flux binding. Here, we report experimental signatures of metallic-like Kondo screening at intermediate temperatures in the Kitaev honeycomb material α-RuCl₃ with dilute Cr³⁺ (S = 3/2) impurities.

We are excited to announce that our joint Sinergia Project: Sustainable Group-IV Active Photonics Research (SUGAR) has been approved for funding by the SNSF and will start in the spring of 2024. SUGAR is an interdisciplinary project that aims to develop a more sustainable photonics platform, based on group IV elements (Si, Ge, Sn). The proposal emphasizes sustainability throughout the entire device life-cycle, incorporating life cycle assessment (LCA) from extraction to end-of-life.

X-rays reveal a non-collinear magnetic state as the base for all-optical magnetization switching.

A large consortium of scientists, coordinated by PSI researchers in the LMS laboratory, led the most comprehensive verification effort so far on computer codes for materials simulations, providing their colleagues with a reference dataset and a set of guidelines for assessing and improving existing and future codes. 

We are happy to announce that the new Cleanroom Name in the Park Innovaare will be PICO = Park Innovaare Cleanroom for Optics and innovation.

Next Step – we will work on a Logo (ideas welcome), together with PiA.

The winner of the naming contest: Helmut Schift

At PSI’s Center for Proton Therapy (CPT), protons are used to treat cancerous tumours in a highly targeted way that spares healthy tissue as much as possible. This is the result of the characteristic way in which charged particles interact with matter, so that a beam of protons deposits most of its energy at a certain depth in a material depending on the energy and the composition of the material. The dedicated medical cyclotron COMET accelerates protons to an energy of 250 MeV, which then have to be "slowed down" so that the energy matches the depth of the tumour to be treated.

Co oxides with perovskite-related structure are particularly promising, cost-effective OER catalysts. However, the increasing Co demand by the battery industry is pushing the search for Co-free alternatives. Here we investigate the potential of the Co-free layered perovskite family RBaCuFeO_5+δ (R = 4f lanthanide), where we identify the critical structural and electronic variables leading to high OER catalytical performance. The employed methodology, based in the use of advanced neutron and X-ray synchrotron techniques combined with ab initio DFT calculations allowed to reveal LaBaCuFeO_5+δ as new, promising Co-free electroctalyst. Moreover, we could show that this material can be industrially produced in nanocrystalline form. We believe that the reported results and methodology may contribute to the implementation of new technologies aimed to generate energy with lower carbon emissions, and can also inspire the scientific community in their search of other Co-free materials with good OER electrocatalytical properties.

Using laser powder bed fusion (LPBF) technology, we devise special processing strategies to ‘program’ the thermal stability of the as-printed alloy, such that it is possible to decide, a priori, how the material’s microstructure will evolve upon heat treatment

One of the challenges in modern research on the fabrication of non-fullerene acceptor based organic solar cells is the availability of very efficient hole transport layers (HTLs). A new approach that avoids mutual solubility issues is to deposit the HTL from a suspension of doped organic nanoparticles. Surface-sensitive TEY-STXM measurements at the PolLux beamline characterised the homogeneity of the dopant in the nanoparticles and develop efficient nanoparticle HTL materials for organic solar cells.

The objective of this project was to determine the contribution from a variety of obstacles to moving dislocations to the nano-indentation stress necessary to initiate plastic flow. The obstacles are characterized by different length scales. Among these characteristic lengths, there are those associated with the material microstructure such as grain size, dislocations density, irradiation-induced defects, and those related to the size of the plastic zone beneath the indenter, or equivalently to the size of the indent. Thus, we can classify the size effects into two categories: structural size effect and indentation size effect (ISE). The underlying idea is to quantify and separate these two effects on the unirradiated material first to be able to properly isolate the contribution of the irradiation defect on the measured hardness from the tests on irradiated materials.

Dr. Cornelius Hempel, head of the Ion Trap Quantum Computation group at LNQ’s ETHZ-PSI Quantum Computing Hub, spoke to SRF to explain how quantum computers work and how future versions of these devices can be used to solve some of the big problems of our time. 

RNA-binding proteins (RBPs) are crucial regulators of gene expression, often composed of defined domains interspersed with flexible, intrinsically disordered regions. Determining the structure of ribonucleoprotein (RNP) complexes involving such RBPs necessitates integrative structural modeling due to their lack of a single stable state. In this study, we integrate magnetic resonance, mass spectrometry, and small-angle scattering data to determine the solution structure of ...

Microcalcifications, small deposits of calcium-containing minerals that form in breast tissue, are often, but not always, a warning sign of breast cancer. The relationship between microcalcifications and cancer has not been fully understood thus far. Researchers discovered now that the relationship between microcalcifications and tumors seems to be linked to the presence of a particular mineral called whitlockite, which is rich in magnesium and is found in microcalcifications only in the absence of tumors.

The MNE (Micro and Nano Engineering) conference is a prestigious annual event that serves as a global platform for experts, researchers, and innovators in the field of micro and nanotechnology. This conference brings together leading minds from academia and industry to share cutting-edge research, exchange ideas, and explore emerging trends and breakthroughs in the world of micro and nanoengineering.

Two-dimensional arrays of magnetically coupled nanomagnets provide a mesoscopic platform for exploring collective phenomena as well as realizing a broad range of spintronic devices. In particular, the magnetic coupling plays a critical role in determining the nature of the cooperative behavior and providing new functionalities in nanomagnet-based devices. Here, we create coupled Ising-like nanomagnets ...

The interplay between spin-orbit interaction and magnetic order is one of the most active research fields in condensed matter physics and drives the search for materials with novel, and tunable, magnetic and spin properties. Here we report on a variety of unique and unexpected observations in thin multiferroic Ge_1−xMn_xTe films.

Magnon polarons are novel elementary excitations possessing hybrid magnonic and phononic signatures, and are responsible for many exotic spintronic and magnonic phenomena. Despite long-term sustained experimental efforts in chasing for magnon polarons, direct spectroscopic evidence of their existence is hardly observed. Here, we report the direct observation of magnon polarons using neutron spectroscopy on a multiferroic Fe₂Mo₃O₈ possessing strong magnon-phonon coupling.

Fifty years after Anderson’s resonating valence-bond proposal, the spin-1/2 triangular-lattice Heisenberg antiferromagnet (TLHAF) remains the ultimate platform to explore highly entangled quantum spin states in proximity to magnetic order. Yb-based delafossites are ideal candidate TLHAF materials, which allow experimental access to the full range of applied in-plane magnetic fields. We perform a systematic neutron scattering study of CsYbSe₂, first proving the Heisenberg character of the interactions and quantifying the second-neighbor coupling.

Dr. Tim A. Butcher from the Microspectroscopy group was awarded the first prize in the "Art in Magnetism" competition of the JEMS 2023 conference with his contribution "Biffo", obtained from a ptychography image of a BiFeO3 nanoplate.

Carbon supports are ubiquitous components of heterogeneous catalysts for acetylene hydrochlorination to vinyl chloride, from commercial mercury-based systems to more sustainable metal single-atom alternatives. Their potential co-catalytic role has long been postulated but never unequivocally demonstrated. Herein, combining operando X-ray absorption spectroscopy with other spectroscopic and kinetic analyses, we evidence the bifunctionality of carbons and metal sites (Pt, Au, Ru) in the acetylene hydrochlorination catalytic cycle.

Increasing the selectivity of a chemical process through rational catalyst design is the Holy Grail of heterogeneous catalysis. Researchers at PSI and ETH Zürich showcase how revealing hidden steps in reaction pathways can steer processes towards preferred products, as demonstrated in a study focused on biomass valorization.

The basis for our understanding of quantum magnetism has been the study of elegantly simple model systems. However, even for the antiferromagnetic honeycomb lattice with isotropic spin interactions – one of the simplest model systems – a detailed understanding of quantum effects is still lacking. Here, using inelastic neutron scattering measurements of the honeycomb lattice material YbCl₃, we elucidate how quantum effects renormalize ...

Chalk River Unidentified Deposits (CRUD) are dissolved and suspended solids, product of the corrosion of structural elements in water circuits of nuclear reactors.  

The chemical composition of CRUD is variable as it depends on the composition of the reactor’s structural material, as well as the types of refueling cycles.  Recent internal investigations have found unexpected but significant Si-amount in CRUD. The chemical composition of CRUD holds key information for an improved understanding of CRUD formation and possible impact in fuel reliability and contamination prevention.

The standard analytical methods available in the hot laboratory did not allow an easy quantitative determination of the Si-amount in CRUD. A new innovative procedure has been developed and tested with synthetic CRUD name Syntcrud.

The adapted flex-fusion digestion method presented here is able to provide reliable concentrations of several elements within CRUD, including Si, which was not possible in methods used previously for ICPMS measurement.

Manipulating the spin state of thin layers of superconducting material is a promising route to generate dissipationless spin currents in spintronic devices. Approaches typically focus on using thin ferromagnetic elements to perturb the spin state of the superconducting condensate to create spin-triplet correlations. We have investigated simple structures that generate spin-triplet correlations without using ferromagnetic elements.

Kagome lattices are intriguing and rich platforms for studying the intertwining of topology, electron correlation, and magnetism. These materials have been subject to tremendous experimental and theoretical studies not only due to their exciting physical properties but also as systems that may solve critical technological problems. We will review recent experimental progress on superconductivity and magnetic fingerprints of charge order in several kagome-lattice systems from the local-magnetic probe point of view by utilizing muon-spin rotation under extreme conditions, i.e., hydrostatic pressure, ultra low temperature and high magnetic field.

Aliovalent doping is a way to optimize the electrical properties of semiconductors, but its impact on the phonon structure and propagation is seldom considered properly. Here we show that aliovalent doping can be much more effective in reducing the lattice thermal conductivity of thermoelectric semiconductors than the commonly employed isoelectronic alloying strategy. We demonstrate ...

The bones of the tree hollow toad tree frog are turquoise blue. Our team is currently investigating the nanostructure of the bone and its significance for the frog.

The helical magnetic structures of cubic chiral systems are well explained by the competition among Heisen- berg exchange, Dzyaloshinskii-Moriya interaction, cubic anisotropy, and anisotropic exchange interaction (AEI). Recently, the role of the latter has been argued theoretically to be crucial for the low-temperature phase diagram of the cubic chiral magnet Cu₂OSeO₃, which features tilted conical and disordered skyrmion states for a specific orientation of the applied magnetic field (μ₀H⃗ ∥ [001]). In this study ...

The current challenge to realizing continuously tunable magnetism lies in our inability to systematically change properties, such as valence, spin, and orbital degrees of freedom, as well as crystallographic geometry. Here, we demonstrate that ferromagnetism can be externally turned on with the application of low-energy helium implantation and can be subsequently erased and returned to the pristine state via annealing.

We are happy to announce the release of MUMOTT (multi-modal tensor tomography) 1.0, an all-Python package for the analysis of tensor tomography measurements! 

Stephan Burkhalter (PhD student in our group) is the recipient of this year’s Lab Award of the Physics Department at ETH Zurich.