Unstable itinerancy: how a pinch of disorder can delocalize carriers of charge and entropy in correlated systems

Materials near a metal-insulator transition are central to many of the most vexing problems in condensed matter. Here I discuss a few examples where electron spin and charge are on the boundary of localization, but not simultaneously. We study how quenched disorder plays a critical role in understanding which quasiparticles emerge and how they can be delocalized near a metal-insulator transition.