Connection between -electron correlations and magnetic excitations in UTe.

The detailed anisotropic dispersion of the low-temperature, low-energy magnetic excitations of the candidate spin-triplet superconductor UTe is revealed using inelastic neutron scattering. The magnetic excitations emerge from the Brillouin zone boundary at the high symmetry and points and disperse along the crystallographic -axis. In applied magnetic fields to at least = 11 T along the , the magnetism is found to be field-independent in the ( 0) plane.

Commissioning of the novel Continuous Angle Multi-energy Analysis spectrometer at the Paul Scherrer Institut.

We report on the commissioning results of the cold neutron multiplexing secondary spectrometer CAMEA (Continuous Angle Multi-Energy Analysis) at the Swiss Spallation Neutron Source at the Paul Scherrer Institut, Switzerland. CAMEA is optimized for efficient data acquisition of scattered neutrons in the horizontal scattering plane, allowing for detailed and rapid mapping of low-energy excitations under extreme sample environment conditions.

Fate of charge order in overdoped La-based cuprates.

In high-temperature cuprate superconductors, stripe order refers broadly to a coupled spin and charge modulation with a commensuration of eight and four lattice units, respectively. How this stripe order evolves across optimal doping remains a controversial question. Here we present a systematic resonant inelastic x-ray scattering study of weak charge correlations in LaSrCuO and LaEuSrCuO.

Complete field-induced spectral response of the spin-1/2 triangular-lattice antiferromagnet CsYbSe.

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 CsYbSe, first proving the Heisenberg character of the interactions and quantifying the second-neighbor coupling.

Emergence of Spinons in Layered Trimer Iridate Ba_{4}Ir_{3}O_{10}.

Spinons are well known as the elementary excitations of one-dimensional antiferromagnetic chains, but means to realize spinons in higher dimensions is the subject of intense research. Here, we use resonant x-ray scattering to study the layered trimer iridate Ba_{4}Ir_{3}O_{10}, which shows no magnetic order down to 0.2 K.

Spin Density Wave versus Fractional Magnetization Plateau in a Triangular Antiferromagnet.

We report an excellent realization of the highly nonclassical incommensurate spin-density wave (SDW) state in the quantum frustrated antiferromagnetic insulator Cs_{2}CoBr_{4}. In contrast to the well-known Ising spin chain case, here the SDW is stabilized by virtue of competing planar in-chain anisotropies and frustrated interchain exchange. Adjacent to the SDW phase is a broad m=1/3 magnetization plateau that can be seen as a commensurate locking of the SDW state into the up-up-down (UUD) spin structure.

How do turbidite systems behave from the hydrogeological point of view? New insights and open questions coming from an interdisciplinary work in southern Italy.

Turbidite successions can behave either as aquitards or aquifers depending on their lithological and hydraulic features. In particular, post-depositional processes can increase rock permeability due to fracture development in the competent layers. Thus, at a local scale, turbidite systems warrant further detailed investigations, aimed at reconstructing reliable hydrogeological models.

Uniaxial pressure induced stripe order rotation in LaSrCuO.

Static stripe order is detrimental to superconductivity. Yet, it has been proposed that transverse stripe fluctuations may enhance the inter-stripe Josephson coupling and thus promote superconductivity. Direct experimental studies of stripe dynamics, however, remain difficult.

Antiferromagnetic excitonic insulator state in SrIrO.

Excitonic insulators are usually considered to form via the condensation of a soft charge mode of bound electron-hole pairs. This, however, presumes that the soft exciton is of spin-singlet character. Early theoretical considerations have also predicted a very distinct scenario, in which the condensation of magnetic excitons results in an antiferromagnetic excitonic insulator state.

Giant phonon anomalies in the proximate Kitaev quantum spin liquid α-RuCl.

The Kitaev quantum spin liquid epitomizes an entangled topological state, for which two flavors of fractionalized low-energy excitations are predicted: the itinerant Majorana fermion and the Z gauge flux. It was proposed recently that fingerprints of fractional excitations are encoded in the phonon spectra of Kitaev quantum spin liquids through a novel fractional-excitation-phonon coupling. Here, we detect anomalous phonon effects in α-RuCl using inelastic X-ray scattering with meV resolution.

Laser-induced transient magnons in SrIrO throughout the Brillouin zone.

Although ultrafast manipulation of magnetism holds great promise for new physical phenomena and applications, targeting specific states is held back by our limited understanding of how magnetic correlations evolve on ultrafast timescales. Using ultrafast resonant inelastic X-ray scattering we demonstrate that femtosecond laser pulses can excite transient magnons at large wavevectors in gapped antiferromagnets and that they persist for several picoseconds, which is opposite to what is observed in nearly gapless magnets. Our work suggests that materials with isotropic magnetic interactions are preferred to achieve rapid manipulation of magnetism.

Charge Condensation and Lattice Coupling Drives Stripe Formation in Nickelates.

Revealing the predominant driving force behind symmetry breaking in correlated materials is sometimes a formidable task due to the intertwined nature of different degrees of freedom. This is the case for La_{2-x}Sr_{x}NiO_{4+δ}, in which coupled incommensurate charge and spin stripes form at low temperatures. Here, we use resonant x-ray photon correlation spectroscopy to study the temporal stability and domain memory of the charge and spin stripes in La_{2-x}Sr_{x}NiO_{4+δ}.

Strong Superexchange in a d^{9-δ} Nickelate Revealed by Resonant Inelastic X-Ray Scattering.

The discovery of superconductivity in a d^{9-δ} nickelate has inspired disparate theoretical perspectives regarding the essential physics of this class of materials. A key issue is the magnitude of the magnetic superexchange, which relates to whether cuprate-like high-temperature nickelate superconductivity could be realized. We address this question using Ni L-edge and O K-edge spectroscopy of the reduced d^{9-1/3} trilayer nickelates R_{4}Ni_{3}O_{8} (where R=La, Pr) and associated theoretical modeling.

Strongly Correlated Charge Density Wave in La_{2-x}Sr_{x}CuO_{4} Evidenced by Doping-Dependent Phonon Anomaly.

The discovery of charge-density-wave-related effects in the resonant inelastic x-ray scattering spectra of cuprates holds the tantalizing promise of clarifying the interactions that stabilize the electronic order. Here, we report a comprehensive resonant inelastic x-ray scattering study of La_{2-x}Sr_{x}CuO_{4} finding that charge-density wave effects persist up to a remarkably high doping level of x=0.21 before disappearing at x=0.

Kondo-Induced Giant Isotropic Negative Thermal Expansion.

Negative thermal expansion is an unusual phenomenon appearing in only a handful of materials, but pursuit and mastery of the phenomenon holds great promise for applications across disciplines and industries. Here we report use of x-ray spectroscopy and diffraction to investigate the 4f-electronic properties in Y-doped SmS and employ the Kondo volume collapse model to interpret the results. Our measurements reveal an unparalleled decrease of the bulk Sm valence by over 20% at low temperatures in the mixed-valent golden phase, which we show is caused by a strong coupling between an emergent Kondo lattice state and a large isotropic volume change.

Exploring itinerant states in divalent hexaborides using rare-earth L edge resonant inelastic x-ray scattering.

We present a study of resonant inelastic x-ray scattering (RIXS) spectra collected at the rare-earth L edges of divalent hexaborides YbB and EuB. In both systems, RIXS-active features are observed at two distinct resonances separated by [Formula: see text] eV in incident energy, with angle-dependence suggestive of distinct photon scattering processes. RIXS spectra collected at the divalent absorption peak resemble the unoccupied 5d density of states calculated using density functional theory.

Evolution of Magnetic Order from the Localized to the Itinerant Limit.

Quantum materials that feature magnetic long-range order often reveal complex phase diagrams when localized electrons become mobile. In many materials magnetism is rapidly suppressed as electronic charges dissolve into the conduction band. In materials where magnetism persists, it is unclear how the magnetic properties are affected.

Ultrafast dynamics of spin and orbital correlations in quantum materials: an energy- and momentum-resolved perspective.

Many remarkable properties of quantum materials emerge from states with intricate coupling between the charge, spin and orbital degrees of freedom. Ultrafast photo-excitation of these materials holds great promise for understanding and controlling the properties of these states. Here, we introduce time-resolved resonant inelastic X-ray scattering (tr-RIXS) as a means of measuring the charge, spin and orbital excitations out of equilibrium.

Chemically-Controlled Stacking of Inorganic Subnets in Coordination Networks: Metal-Organic Magnetic Multilayers.

Coordination networks (CNs), such as, for instance, metal-organic frameworks (MOFs), can turn into remarkable magnets, with various topologies of spin carriers and unique opportunities of cross-coupling to other functionalities. Alternatively, distinct inorganic subnetworks that are spatially segregated by organic ligands can lead to coexisting magnetic systems in a single bulk material. Here, we present a system of two CNs of general formula Mn(HO) (OOC-(CH) -COO).

Distinct domain switching in NdCeCoIn at low and high fields.

NdCeCoIn features a magnetic field-driven quantum phase transition that separates two antiferromagnetic phases with an identical magnetic structure inside the superconducting condensate. Using neutron diffraction we demonstrate that the population of the two magnetic domains in the two phases is affected differently by the rotation of the magnetic field in the tetragonal basal plane. In the low-field SDW-phase the domain population is only weakly affected while in the high-field Q-phase they undergo a sharp switch for fields around the a-axis.

Spin Resonance and Magnetic Order in an Unconventional Superconductor.

Unconventional superconductivity in many materials is believed to be mediated by magnetic fluctuations. It is an open question how magnetic order can emerge from a superconducting condensate and how it competes with the magnetic spin resonance in unconventional superconductors. Here we study a model d-wave superconductor that develops spin-density wave order, and find that the spin resonance is unaffected by the onset of static magnetic order.

Field-induced magnetic instability within a superconducting condensate.

The application of magnetic fields, chemical substitution, or hydrostatic pressure to strongly correlated electron materials can stabilize electronic phases with different organizational principles. We present evidence for a field-induced quantum phase transition, in superconducting NdCeCoIn, that separates two antiferromagnetic phases with identical magnetic symmetry. At zero field, we find a spin-density wave that is suppressed at the critical field μ* = 8 T.

Distinct vortex-glass phases in Yb₃Rh₄Sn₁₃ at high and low magnetic fields.

The vortex lattice (VL) in the mixed state of the stannide superconductor Yb3Rh4Sn13 has been studied using small-angle neutron scattering (SANS). The field dependences of the normalized longitudinal and transverse correlation lengths of the VL, ξ(L)/a0 and ξ(T)/a0, reveal two distinct anomalies that are associated with vortex-glass phases below μ0Hl ≈ 700 G and above μ0Hh ∼ 1.7 T (a0 is the intervortex distance).

The Autism-Spectrum Quotient--Italian version: a cross-cultural confirmation of the broader autism phenotype.

The Autism Spectrum Quotient (AQ) has been used to define the 'broader' (BAP), 'medium' (MAP) and 'narrow' autism phenotypes (NAP). We used a new Italian version of the AQ to test if difference on AQ scores and the distribution of BAP, MAP and NAP in autism parents (n = 245) versus control parents (n = 300) were replicated in a Sicilian sample. Parents of children with autism spectrum conditions scored higher than the control parents on total AQ, social skills and communication subscales, and exhibited higher rates of BAP, MAP and NAP.