Kondo Effect of a Vibrating Magnetic Ion

In the presence of coupling with conduction electrons, an s -orbital magnetic ion vibrating in a cage shows rich variety of Kondo effects. In addition to the conventional s -wave Kondo effect, Yu–Anderson type Kondo and phonon-assisted p -wave Kondo effects are possible. It is shown that the low energy fixed points are classified into either the s -channel Kondo or the p -channel one. The Yu-Anderson type Kondo belongs to the s -channel fixed points. On the boundary between the two different types of fixed points two-channel Kondo effect is generically observed.