The positive muon as a small polaron

Abstract

A positive muon in a solid is typically taken to selftrap and move in analogy with an electronic small polaron. Here the dynamics of self-trapping and small-polaron motion are described. It is stressed that the physical circumstances defining electronic and light-interstitial small-polaron formation and motion differ qualitatively from one another. The muon is an intermediate case which in some instances is a unique hybrid of these two situations.