The physics and chemistry of heavy elements, principally lanthanides and 5d transition metals, is distinguished by strong spin-orbit coupling, which can have a dramatic effect on materials properties. The scientific understanding of spin-orbit coupling in 5d atoms is especially challenging and rewarding because the 5d orbitals become involved in partially covalent bonds with neighboring anions. Interest in 4 and 5d oxides, chalcogenides, and pnictides has blossomed in recent years in response to scientific advances and applications in the areas of hard magnets, topological insulators, multiferroics, superconductors, and thermoelectrics. An in-depth comparison between theory and experiment has, however, been missing, and new cross-disciplinary theoretical- computational-experimental collaborations are needed to advance this field.

The program of the proposed workshop will focus on understanding how spin-orbit coupling enhances functionality in compounds containing 5d ions. Specifically, we wish to clarify how properties depend on control parameters such as strength of spin-orbit coupling, d-shell filling, dimensionality, structural distortions, and mixing of 3d and 5d ions for greater chemical flexibility. We will also seek to identify the key factors needed to develop materials with strong magnetocrystalline anisotropy, interesting topological properties, novel charge/orbital order or superconductor pairing mechanisms, and giant magnetoelectric, multiferroic, or magneto-optic effects. The workshop will include theorists, computational scientists, and experimentalists working actively on these topics.