Pseudosymmetry in Tetragonal Perovskite SrIrO Synthesized under High Pressure.

In this study, we report a tetragonal perovskite structure of SrIrO (4/, = 3.9362(9) Å, = 7.880(3) Å) synthesized at 6 GPa and 1400 °C, employing the ambient pressure monoclinic SrIrO with distorted 6 structure as a precursor.

Non-Centrosymmetric SrIrO Obtained Under High Pressure.

SrIrO with strong spin-orbit coupling and Hubbard repulsion (U) hosts Mott insulating states. The similar crystal structure and magnetic and electronic properties, particularly the -wave gap observed in SrIrO enhanced the analogies to the cuprate high- superconductor, LaCuO. The incomplete analogy was due to the lack of broken inversion symmetry phases observed in SrIrO.

Dynamical Structure Factor of the Three-Dimensional Quantum Spin Liquid Candidate NaCaNi_{2}F_{7}.

We study the dynamical structure factor of the spin-1 pyrochlore material NaCaNi_{2}F_{7}, which is well described by a weakly perturbed nearest-neighbour Heisenberg Hamiltonian, Our three approaches-molecular dynamics simulations, stochastic dynamical theory, and linear spin wave theory-reproduce remarkably well the momentum dependence of the experimental inelastic neutron scattering intensity as well as its energy dependence with the exception of the lowest energies. We discuss two surprising aspects and their implications for quantum spin liquids in general: the complete lack of sharp quasiparticle excitations in momentum space and the success of the linear spin wave theory in a regime where it would be expected to fail for several reasons.

Scattering continuum and possible fractionalized excitations in α-RuCl(3).

The combination of electronic correlation and spin-orbit coupling is thought to precipitate a variety of highly unusual electronic phases in solids, including topological and quantum spin liquid states. We report a Raman scattering study that provides evidence for unconventional excitations in α-RuCl_{3}, a spin-orbit coupled Mott insulator on the honeycomb lattice. In particular, our measurements reveal unusual magnetic scattering, typified by a broad continuum.