Two-Channel Kondo Model as a Fixed Point of Local Electron-Phonon Coupling System

概要

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It is shown on the basis of the znultiplicative renormalization-grotrp method of two-loop orderthat the low-energy effectuve Hanailtonian of a strongly coupled local electron-phonon systeznis naapped to the two-channel Kondo model. A phonon is treated as an Einstein oscillatorwith restricted Hilbert space such that Llp to one-phonon process is taken into account. Byeliminating the high energy process of condtrction electrons, it is shown tlaat a certain class ofcouplings between ion vibrations and conduction electrons is selectively grown up. As a resultthe system is reduced to the two-channel Kondo model. The crossover temperattrre Ty and therenormalized phonon frequency A" are expressed in terms of the mass ratio m/M , m and A/I beingthe mass of electron and Jon, and the electron-phonon cotrpling g/D, D being half tlae bandwidthof conductzon electrons. The anomalous behaviors associated with this renorrnalization can bemesuarable if the condition Tz >A" is fulfilled. It is demonstrated that stuch condition issatisfied when g/D is sufficiently large btrt in a realistic range.
社団法人日本物理学会の論文
1996-09-15