SINQ Publication Highlights

The topological nature of the electronic bands or spin structure has direct manifestation in experimentally measured Hall conductivity. The extra topological (or geometrical) component to the Hall effect (THE) usually emerges due to multi-k structures, which inherently possess a finite static scalar spin chirality (SSC). Generating a THE in a single-k structure necessitates the consideration of the dynamical  origin of SSC, the real material examples of such cases remain scarce to date.

Magnetically intercalated transition metal dichalcogenides (TMDs) provide a versatile three-dimensional (3D) material platform to explore quantum phenomena and functionalities that emerge from an intricate interplay among magnetism, band structure, and electronic correlations. 

The Airy wave packet is a solution to the potential-free Schrödinger equation that exhibits remarkable properties such as self-acceleration, nondiffraction, and self-healing. Although Airy beams are now routinely realized ....

Multiband superconductivity arises when multiple electronic bands contribute to the formation of the superconducting state, allowing distinct pairing interactions and gap structures. Here, we present field- and temperature-dependent data  ...

The spiral spin liquid (SSL) is a highly degenerate state characterized by a continuous contour or surface in reciprocal space spanned by a spiral propagation vector. Although the SSL state has been predicted in a number of various theoretical models, very few materials are so far experimentally identified to host such a state. Via combined single-crystal wide-angle and small-angle neutron scattering, we report observation  ...

Superconducting domes, ubiquitous across a variety of quantum materials, are often understood as a window in which pairing is favored, opened by the fluctuations of competing orders. Yet, the understanding of how such a window closes is missing. Here, we show that inelastic neutron scattering ...

Encoding information in antiferromagnetic (AFM) domains is a promising solution for the ever growing demand in magnetic storage capacity. The absence of a macroscopic magnetization avoids crosstalk between different domain states, enabling ultrahigh density spintronics while being detrimental to the domain detection and manipulation. Disentangling these merits and disadvantages seemed so far unattainable. We report evidence ...

Spin moiré superlattices (SMSs) formed by interfacing conventional electronic states with a multi-q magnetic lattice have been proposed as a magnetic analog of crystallographic moiré systems. The electron-minibands created in an SMS are expected to be enriched by the vector-field nature of the magnetic interaction and offer new types of moiré tunability, topological protection, and Berry curvature effects. However, most spin-vortex-hosting systems discovered to date have carrier mean free paths l_mfp significantly shorter than their spin-moiré lattice constant a_spin, inhibiting mini-band-formation. Furthermore ...

The detailed anisotropic dispersion of the low-temperature, low-energy magnetic excitations of the candidate spin-triplet superconductor UTe₂ is revealed using inelastic neutron scattering. The magnetic excitations emerge from the Brillouin zone boundary at the high symmetry Y and T points and disperse along the crystallographic b-axis. In applied magnetic fields ...

Methods to prepare and characterize neutron helical waves carrying orbital angular momentum (OAM) were recently demonstrated at small-angle neutron scattering (SANS) facilities. These methods enable access to the neutron orbital degree of freedom which provides new avenues of exploration in fundamental science experiments as well as in material characterization applications. 

However, ....

Additive manufacturing (AM) or “3D printing” of metals, which builds structure layer by layer, has revolutionized the production of intricate 3D designs. Among its techniques, laser powder bed fusion (PBF-LB) excels in creating metallic parts with intricate designs and high precision. This process can combine different metals into innovative multi-material components with tailored properties, with regards to e.g., strength and thermal conductivity, surpassing the capabilities of single-material designs. However, ....

Magnetic, thermodynamic, neutron diffraction and inelastic neutron scattering are used to study spin correlations in the easy-axis XXZ triangular lattice magnet K₂Co(SeO₃)₂. Despite the presence of quasi-2D “supersolid” magnetic order, the low-energy excitation spectrum contains no sharp modes and is instead a broad and structured multiparticle continuum. Applying a weak magnetic field ...

Topologically nontrivial magnetic structures such as skyrmion lattices are well known in materials lacking lattice inversion symmetry, where antisymmetric exchange interactions are allowed. Only recently, topological multi-q magnetic textures that spontaneously break the chiral symmetry, for example, three-dimensional hedgehog lattices, were discovered in centrosymmetric compounds, where they are instead driven by frustrated interactions. Here we show that ...

Quantum critical points (QCPs), zero-temperature phase transitions, are win- dows to fundamental quantum-mechanical phenomena associated with universal behaviour. Magnetic QCPs have been extensively investigated in the vicinity of antiferromagnetic order. However, QCPs are rare in metallic ferromagnets due to the coupling of the order parameter to electronic soft modes. Recently, antisymmetric spin-orbit coupling in noncentrosymmetric systems was suggested to protect ferromagnetic QCPs. Nonetheless, multiple centrosymmetric materials ...

Frustrated magnets with ordered magnetic spiral phases that spontaneously break inversion symmetry have received significant attention from both fundamental and applied sciences communities due to the experimental demonstration that some of these materials can couple to the lattice and induce electric polarization. In these materials, the common origin of the electric and magnetic orders guarantees substantial coupling between them, which is highly desirable for applications ...

The recent discovery of superconductivity in infinite layer thin films and bulk Ruddlesden–Popper nickelates has stimulated the investigation of other predicted properties of these materials. Among them, the existence of magnetism-driven ferroelectricity in the parent compounds RNiO₃ (R = 4f lanthanide and Y) at the onset of the Néel order, T_N, has remained particularly elusive. Using diffraction techniques, we reveal here the existence of magnetostriction at T_N in bulk YNiO₃ single crystals. Interestingly, the associated lattice anomalies ...

A hallmark of unconventional superconductors is a complex electronic phase diagram where intertwined orders of charge-spin-lattice degrees of freedom compete and coexist. While the kagome metals such as CsV₃Sb₅ also exhibit complex behavior, involving coexisting charge density wave order and superconductivity, much is unclear about the microscopic origin of the superconducting pairing. We study the vortex lattice in the superconducting state of Cs(V_0.86Ta_0.14)₃Sb₅, where the Ta-doping suppresses charge order and enhances superconductivity. Using small-angle neutron scattering ...

Van-der-Waals magnetic materials can be exfoliated to realize ultrathin sheets or interfaces with highly controllable optical or spintronics responses. In majority, these are collinear ferro-, ferri-, or antiferromagnets, with a particular scarcity of lattice-incommensurate helimagnets of defined left- or right-handed rotation sense, or helicity. Here, we report polarized neutron scattering experiments on DyTe₃, whose layered structure has highly metallic tellurium layers separated by double-slabs of dysprosium square nets...

Emergent quasiparticles with a Dirac dispersion in condensed matter systems can be described by the Dirac equation for relativistic electrons, in analogy with Dirac particles in high-energy physics. For example, electrons with a Dirac dispersion have been intensively studied in electronic systems such as graphene and topological insulators. However, charge is not a prerequisite for Dirac fermions, and the emergence of Dirac fermions without a charge degree of freedom has been theoretically predicted to be realized in Dirac quantum spin liquids. These quasiparticles ...

LiCu₃O₃ is an antiferromagnetic mixed valence cuprate where trilayers of edge-sharing Cu(II)O (3d⁹) are sandwiched in between planes of Cu(I) (3d¹⁰) ions, with Li stochastically substituting Cu(II). Angle-resolved photoemission spectroscopy (ARPES) and density functional theory reveal two insulating electronic subsystems that are segregated in spite of sharing common oxygen atoms: a Cu d_z²/O p_z derived valence band (VB) dispersing on the Cu(I) plane, and a Cu 3d_x²−y²/O 2p_x,y derived Zhang-Rice singlet (ZRS) band dispersing on the Cu(II)O planes.

In quantum magnetic materials, ordered phases induced by an applied mag- netic field can be described as the Bose-Einstein condensation (BEC) of mag- non excitations. In the strongly frustrated system SrCu₂(BO₃)₂, no clear magnon BEC could be observed, pointing to an alternative mechanism, but the high fields required to probe this physics have remained a barrier to detailed investigation.Here we exploit the first purpose-built high-field neutron scattering facility to measure ...

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 ...

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.

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.

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 ...

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.

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 ...