Phonon frequency shift and effect of correlation on the electron-phonon interaction in heavy fermion systemsB OJHA, P NAYAK and S N BEHERA*P.G. Department of Physics, Sambalpur University, Jyoti Vihar, Burla 768 019, India Abstract The electron-phonon interaction in the periodic Anderson model (PAM) is considered. The PAM incorporates the effect of onsite Coulomb interaction (U) between f-electrons. The influence of Coulomb correlation U on the phonon response of the system is studied by evaluating the phonon spectral function for various parameters of the model. The numerical evaluation of the spectral function is carried out in the long wavelength limit at finite temperatures keeping only linear terms in U. The observed behaviour is found to agree well with the general features obtained experimentally for some heavy fermion (HF) systems. Keywords Periodic Anderson model (PAM); heavy fermion system; electron-phonon interaction; Coulomb correlation; double time temperature dependent Green function.Pacs No 74.70.Tx; 71.10.-w; 71.38.+i |