Effective mass decrease due to electron-phonon interaction in heavy fermion systems

1993 ◽  
Vol 90 (1) ◽  
pp. 125-126 ◽  
Author(s):  
P. Fulde ◽  
P. Horsch ◽  
A. Ramšak
Keyword(s):  
Effective Mass ◽  
Heavy Fermion ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Fermion Systems ◽  
Heavy Fermion Systems

Electron-phonon interaction in heavy fermion systems

1990 ◽  
Vol 163 (1-3) ◽  
pp. 667-669
Author(s):  
J. Keller ◽  
R. Bulla ◽  
Th. Höhn ◽  
K.W. Becker
Keyword(s):  
Heavy Fermion ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Fermion Systems ◽  
Heavy Fermion Systems

Electron-phonon interaction in heavy-fermion systems

1990 ◽  
Vol 41 (4) ◽  
pp. 1878-1888 ◽  
Author(s):  
J. Keller ◽  
R. Bulla ◽  
Th. Höhn ◽  
K. W. Becker
Keyword(s):  
Heavy Fermion ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Fermion Systems ◽  
Heavy Fermion Systems

INFLUENCE OF ELECTRON–PHONON INTERACTION ON EFFECTIVE MASS IN SOME HEAVY FERMION (HF) SYSTEMS

2008 ◽  
Vol 22 (04) ◽  
pp. 365-379 ◽  
Author(s):  
S. MOHANTY ◽  
B. K. KALTA ◽  
P. NAYAK
Keyword(s):  
Effective Mass ◽  
Coupling Strength ◽  
Heavy Fermion ◽  
Simple Expression ◽  
Model Parameters ◽  
Coupling Mechanism ◽  
Phonon Coupling ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Electron Phonon Coupling

It is a fact that for ordinary metals, the electron–phonon interaction increases the quasi-particle mass, which is in contrast to the finding by Fulde et al. that, for some heavy Fermion (HF) systems, it decreases. Some experiments on HF systems suggest that there exists a strong coupling of the elastic degrees of freedom with these at the electronic and magnetic ones. To understand the effect of electron–phonon interaction on effective mass, the electron–phonon coupling mechanism in the framework of the periodic Anderson model is considered, and a simple expression is derived. This involves various model parameters namely, the position of the 4f level; the effective coupling strength, g, temperature, b; and the electron–phonon coupling strength, r. The influence of these parameters on the value of effective mass is studied, and interesting results were found. For simplicity, the numerical calculation is performed in the long wavelength limit.

ELECTRON-PHONON INTERACTION AND PHONON RESPONSE IN HEAVY FERMION SYSTEMS

2002 ◽  
Vol 16 (24) ◽  
pp. 3595-3613 ◽  
Author(s):  
P. NAYAK ◽  
B. OJHA ◽  
S. MOHANTY ◽  
S. N. BEHERA
Keyword(s):  
Heavy Fermion ◽  
Spectral Density Function ◽  
Response Property ◽  
Model Parameters ◽  
Phonon Interaction ◽  
Long Wavelength ◽  
Electron Phonon Interaction ◽  
Fermion Systems ◽  
Electron Phonon Coupling ◽  
Phonon Excitation

The phonon response property of the Heavy Fermion (HF) systems are investigated within the Periodic Anderson Model (PAM) to explain the observed phonon anomalies. To understand the microscopic origin of these anomalies, two different mechanisms of electron-phonon interaction, namely, the usual interaction between the phonons and the electrons in the f-bands as well as the interaction due to the hybridization term of PAM, are considered. The influence of coulomb correlation U on the phonon excitation spectrum and the spectral density function are studied for various model parameters, namely, the position of the f-level E0, the ratio r of the electron-phonon coupling strengths f1(q) and f2(q), and the effective coupling strength g. The numerical evaluations of these phonon response functions are carried out for small temperatures in the long wavelength limit, while retaining terms which are linear in correlation. The observed behavior agrees well with the general features obtained in experiment.

Phonon response of some heavy Fermion systems in dynamic limit

2017 ◽  
Vol 31 (12) ◽  
pp. 1750090
Author(s):  
Jitendra Sahoo ◽  
Namita Shadangi ◽  
Pratibindhya Nayak
Keyword(s):  
Heavy Fermion ◽  
Periodic Anderson Model ◽  
Temperature Dependent ◽  
Effective Coupling ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Fermion Systems ◽  
Phonon Excitation ◽  
Double Time ◽  
Strength Formula

The phonon excitation spectrum of some Heavy Fermion (HF) systems in the presence of electron–phonon interaction is studied in the dynamic limit ([Formula: see text]). The renormalized excitation phonon frequencies ([Formula: see text]) are evaluated through Periodic Anderson Model (PAM) in the presence of electron–phonon interaction using Zubarev-type double time temperature-dependent Green function. The calculated renormalized phonon energy is analyzed through the plots of ([Formula: see text]) against temperature for different system parameters like effective coupling strength ‘[Formula: see text]’ and the position of [Formula: see text]-level ‘[Formula: see text]’. The observed behavior is analyzed and found to agree with the general features of HF systems found in experiments. Further, it is observed that in finite but small [Formula: see text]-values the propagating phonons harden and change to localized peaks.

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