Longer-range lattice anisotropy strongly competing with spin-orbit interactions in pyrochlore iridates

In the search for topological phases in correlated electron systems, materials with 5d transition-metal ions, in particular the iridium-based pyrochlores A2Ir2O7, provide fertile grounds. Several topological states have been predicted but the actual realization of such states is believed to critically depend on the strength of local potentials arising from distortions of the IrO6 cages. We test this hypothesis by measuring with resonant …