Electrical transport and spectroscopy studies of the delafossite layered metals

The delafossites, named after the French crystallographer Gabriel Delafosse, are triangular lattice layered materials with general formula ABO₂.  The family includes insulators, large gap semiconductors and a few astonishingly high conductivity metals.  I will describe our group’s work on the latter, focusing on three aspects of our recent research.  Firstly, I will discuss the realization that the high electrical conductivity results from a degree of crystalline purity that is highly unusual in a multi-component oxide, and in the second part of the talk I will describe novel spectroscopic signatures that arise from studying angle-resolved photoemission (ARPES) from the layered Mott insulator – metal system PdCrO₂.   I will close by describing the discovery of what we believe to be an entirely new quantum coherent phenomenon in the inter-layer transport of PdCoO₂ and PtCoO₂.