Prof Radu Coldea

Abstract:

The deposited package contains single crystal inelastic neutron scattering data of the triangular lattice antiferromagnet Ba3CoSb2O9; the zip file contains a series of ASCII data files, MATLAB plotting functions and a README.txt file that explains the data file formats.

Abstract:

See Readme.txt for details.

Abstract:

We report structural studies of the spin-orbit Mott insulator family K x Ir y O 2 , with triangular layers of edge-sharing IrO 6 octahedra bonded by potassium ions. The potassium content acts as a chemical tuning parameter to control the amount of charge in the Ir-O layers. Unlike the isostructural families with Ir replaced by Co or Rh ( y = 1 ), which are metallic over a range of potassium compositions x , we instead find insulating behavior with charge neutrality achieved via iridium vacancies, which order in a honeycomb supercell above a critical composition x c . By performing density functional theory calculations we attribute the observed behavior to a subtle interplay of crystal-field environment, local electronic correlations, and strong spin-orbit interaction at the Ir 4 + sites, making this structural family a candidate to display Kitaev magnetism in the experimentally unexplored regime that interpolates between triangular and honeycomb structures.