Two‐Channel Kondo Physics: From Engineered Structures to Quantum Materials Realizations. Issue 5 (17th March 2020) - Kirchner, Stefan
Abstract: The Kondo effect assumes a central role in condensed matter physics. It describes the exchange scattering of electrons with a localized moment and occurs in a wide range of settings from rare earth‐based intermetallics to nanotubes and semiconductor heterostructures. A conceptually simple extension of the model, known as the two‐channel Kondo model, can give rise to singular scattering and the formation of an unconventional metal. Although the observation of the standard Kondo effect has become ubiquitous, its two‐channel counterpart has been proven difficult to realize. This article reviews attempts, challenges, and successes in realizing the two‐channel Kondo effect in artificial structures and real quantum materials. Abstract : An ever‐growing number of complex materials have been identified that defy the standard theory of metals. One of the simplest ways of conceptualizing an unconventional metal state is in terms of the two‐channel Kondo effect. This effect describes the formation of a fragile many‐body state which results from an intricate interplay of localized and itinerant degrees of freedom. This article reviews challenges, attempts, and successes of realizing this two‐channel Kondo effect in engineered structures and real quantum materials.