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Antiferromagnetically coupled S=1/2 spins on an isotropic triangular latticeis the paradigm of frustrated quantum magnetism, but structurally idealrealizations are rare. Here we investigate NaYbO$_2$, which hosts an idealtriangular lattice of $J_{eff}=1/2$ moments with no inherent site disorder. Nosignatures of conventional magnetic order appear down to 50 mK, stronglysuggesting a quantum spin liquid ground state. We observe a two-peak specificheat and a nearly quadratic temperature dependence in accord with expectationsfor a two-dimensional Dirac spin liquid. Application of a magnetic fieldstrongly perturbs the quantum disordered ground state and induces a cleartransition into a collinear ordered state consistent with a long-predictedup-up-down structure for a triangular lattice XXZ Hamiltonian driven by quantumfluctuations. The observation of spin liquid signatures in zero field andquantum-induced ordering in intermediate fields in the same compounddemonstrate an intrinsically quantum disordered ground state. We conclude thatNaYbO$_2$ is a model, versatile platform for exploring spin liquid physics withfull tunability of field and temperature.

Despite impressive advances in the broad field of innate immunity, our understanding of the molecules and signaling pathways that control the host immune response to nematode infection remains incomplete. We have shown recently that Transforming Growth Factor-β (TGF-β) signaling in the fruit fly Drosophila melanogaster is activated by nematode infection and certain TGF-β superfamily members regulate the D. melanogaster anti-nematode immune response. Here, we investigate the effect of an entomopathogenic nematode infection factor on host TGF-β pathway regulation and immune function. We find that Heterorhabditis bacteriophora serine carboxypeptidase activates the Activin branch in D. melanogaster adults and the immune deficiency pathway in Activin-deficient flies, it affects hemocyte numbers and survival in flies deficient for Activin signaling, and causes increased intestinal steatosis in Activin-deficient flies. Thus, insights into the D. melanogaster signaling pathways and metabolic processes interacting with H. bacteriophora pathogenicity factors will be applicable to entomopathogenic nematode infection of important agricultural insect pests and vectors of disease. [ABSTRACT FROM AUTHOR]

This parent information project is grounded in the notion of parental involvement as advocacy that benefits children in the community. Supported by a state-level early childhood foundation in a learning partnership with a national, non-partisan research foundation, this project engaged parent leaders from five communities as co-researchers in identifying assets, listening to citizens, capacity building, and knowledge development. University researchers engaged with co-researchers as essential collaborators enacting this participatory action-oriented project in order to gain insights on family involvement and community action contributing to thriving children, birth to age 8. Creation of a deliberation guide was a tangible product of an iterative cycle of inquiry and grassroots, collaborative process to promote change and empowerment. Co-researcher insights and observations, formally captured in an intentional focus group, are presented with equal importance as author voices. The use of face-to-face time and virtual space is addressed. Implications for parent leadership, transformative knowledge production, and educational change are explored. [ABSTRACT FROM AUTHOR]

High carrier density quantum wells embedded within a Mott insulating matrix present a rich arena for exploring unconventional electronic phase behavior ranging from non-Fermi-liquid transport and signatures of quantum criticality to pseudogap formation. Probing the proposed connection between unconventional magnetotransport and incipient electronic order within these quantum wells has however remained an enduring challenge due to the ultra-thin layer thicknesses required. Here we address this challenge by exploring the magnetic properties of high-density SrTiO3 quantum wells embedded within the antiferromagnetic Mott insulator SmTiO3 via muon spin relaxation and polarized neutron reflectometry measurements. The one electron per planar unit cell acquired by the nominal d0 band insulator SrTiO3 when embedded within a d1 Mott SmTiO3 matrix exhibits slow magnetic fluctuations that begin to freeze into a quasistatic spin state below a critical temperature T*. The appearance of this quasistatic well magnetism coincides with the previously reported opening of a pseudogap in the tunneling spectra of high carrier density wells inside this film architecture. Our data suggest a common origin of the pseudogap phase behavior in this quantum critical oxide heterostructure with those observed in bulk Mott materials close to an antiferromagnetic instability. Oxide heterostructures: origins of a pseudogap Magnetic correlations may drive 'pseudogap' physics in a complex oxide device, suggesting a connection to high-temperature superconductors. The mechanism underlying the so-called pseudogap state, a regime of unconventional electronic behavior, is one of the central mysteries of high-temperature superconductivity in cuprate materials. A team led by Stephen Wilson at the University of California, Santa Barbara studied the magnetic response of another system with a pseudogap, an artificial structure made by combining samarium and strontium titanate thin films. They found that the pseudogap formation coincided with the observation of antiferromagnetic correlations, indicating that short-range magnetic ordering may be the source of the pseudogap. A similar mechanism has been proposed to play a role in the cuprates, suggesting that a more detailed understanding of these oxide heterostructures could yield insights that apply to high-temperature superconductors as well. [ABSTRACT FROM AUTHOR]

We have carried out muon spin relaxation and rotation measurements on the newly discovered kagome metal KV 3 Sb 5 , and find a local field dominated by weak magnetic disorder which we associate with the nuclear moments present, and a modest temperature dependence which tracks the bulk magnetic susceptibility. We find no evidence for the existence of V 4+ local moments, suggesting that the physics underlying the recently reported giant unconventional anomalous Hall effect in this material warrants further studies., (© 2021 IOP Publishing Ltd.)

We investigate the magnetic properties of LiYbO 2 , containing a three-dimensionally frustrated, diamond-like lattice via neutron scattering, magnetization, and heat capacity measurements. The stretched diamond network of Yb 3+ ions in LiYbO 2 enters a long-range incommensurate, helical state with an ordering wave vector k = ( 0.384 , ± 0.384 , 0 ) that "locks-in" to a commensurate k = ( 1 / 3 , ± 1 / 3,0 ) phase under the application of a magnetic field. The spiral magnetic ground state of LiYbO 2 can be understood in the framework of a Heisenberg J 1 - J 2 Hamiltonian on a stretched diamond lattice, where the propagation vector of the spiral is uniquely determined by the ratio of J 2 / J 1 . The pure Heisenberg model, however, fails to account for the relative phasing between the Yb moments on the two sites of the bipartite lattice, and this detail as well as the presence of an intermediate, partially disordered, magnetic state below 1 K suggests interactions beyond the classical Heisenberg description of this material.