Non-Fermi-liquid behavior of impurity Anderson model with non-Kramers doublet ground state

We investigate the non-Fermi-liquid (NFL) behaviour of an impurity Anderson model which has an f(2) configuration subject to a tetragonal crystalline electric field (CEF), giving a ground state which is a non-Kramers doublet. The temperature dependence of the specific heat in a magnetic field is calculated. When the magnetic field is very weak, there are two peaks: one is a broad peak around 5T*, where T* is the temperature at which the - In T dependence of the magnetic susceptibility and the gamma-coefficient of the specific heat, associated with the NFL behaviour, begins. The other peak is at very low temperatures and shows a release of the residual entropy which is expected from the NFL slate of a two-channel type Kondo model. (C) 1999 Published by Elsevier Science B.V. All rights reserved.