Interface structure of SrTiO3-LaAlO3 at elevated temperatures studied in-situ by synchroton x-rays

The atomic interface structure between SrTiO3 and LaAlO3 was studied at elevated temperatures employing in situ surface x-ray diffraction. The results at 473 K indicate that the lattice distorts significantly in two ways. First, the interatomic distances between the cations across the interface become as large as 4.03(2) Å. Second, the TiO6 octahedra at the interface contract their principal axis along the surface normal considerably and the Ti displaces off center. These distortions can be ascribed to the charge inbalance introduced by the change in atomic species across the interface and to a Jahn-Teller effect. The latter distortion suggests the presence of extra electrons at the interface, which is important for understanding the electronic properties of this system

Magnetic anisotropy of individually addressed spin states

Controlling magnetic anisotropy is a key requirement for the fundamental understanding of molecular magnetism and is a prerequisite for numerous applications in magnetic storage, spintronics, and all-spin logic devices. In order to address the question of molecular magnetic anisotropy experimentally, we have synthesized single crystals of a molecular spin system containing four antiferromagnetically coupled s=5/2 manganese(II) ions. Using low-temperature cantilever magnetometry, we demonstrate the selective population of the S=0,1,...,10 spin states upon application of magnetic fields up to 33 T and map the magnetic anisotropy of each of these states. We observe a strong dependence of the shape and size of the magnetic anisotropy on the populated spin states, and, in particular, reveal an anisotropy reversal upon going from the lowest to the highest spin state

Evidence for Strong Electron Correlations in a Nonsymmorphic Dirac Semimetal

Metallic iridium oxides (iridates) provide a fertile playground to explore new phenomena resulting from the interplay between topological protection, spin-orbit and electron-electron interactions. To date, however, few studies of the low energy electronic excitations exist due to the difficulty in synthesising crystals with sufficiently large carrier mean-free-paths. Here, we report the observation of Shubnikov-de Haas quantum oscillations in high-quality single crystals of monoclinic SrIrO3 in magnetic fields up to 35 T. Analysis of the oscillations reveals a Fermi surface comprising multiple small pockets with effective masses up to 4.5 times larger than the calculated band mass. Ab-initio calculations reveal robust linear band-crossings at the Brillouin zone boundary, due to its non-symmorphic symmetry, and overall we find good agreement between the angular dependence of the oscillations and the theoretical expectations. Further evidence of strong electron correlations is realized through the observation of signatures of non-Fermi liquid transport as well as a large Kadowaki-Woods ratio. These collective findings, coupled with knowledge of the evolution of the electronic state across the Ruddlesden-Popper iridate series, establishes monoclinic SrIrO3 as a topological semimetal on the boundary of the Mott metal-insulator transition. © 2021, The Author(s).We gratefully acknowledge useful discussions with A. Rost and D. F. McMorrow. We would also like to thank G. Stenning and D. Nye for help with the instruments in the Materials Characterisation Laboratory at the ISIS Neutron and Muon Source, Kuang-Yu Samuel Chang and Roos Leenen for technical assistance with the DFT calculations, and Sebastian Bette for XRD characterizations. We acknowledge the support of the HFML-Radboud University (RU)/Netherlands Organisation for Scientific Research (NWO), a member of the European Magnetic Field Laboratory. This work is part of the research program Strange Metals (Grant 16METL01) of the former Foundation for Fundamental Research on Matter, which is financially supported by the NWO and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 835279-Catch-22). We gratefully acknowledge support from the UK Engineering and Physical Sciences research council, grant EP/N034694/1. We acknowledge collaborative support from A.S. Gibbs, D. Fortes and the ISIS Crystallography Group for making available the 193Ir for the isotope work. Experiments at the ISIS Neutron and Muon Source were supported by a beamtime allocation RB1990395, DOI:10.5286/ISIS.E.RB1990395, from the Science and Technology Facilities Council. The work of D. P. and V. M. was supported by Act 211 Government of the Russian Federation, contract 02.A03.21.0006

Securing Important Strigolactone Key Structures: Orobanchol and 5-Deoxystrigol

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