Heavy Fermion Systems

The book on Heavy-Fermion Systems is a part of the Book series "Handbook of Metal Physics", each volume of which is written to facilitate the research of Ph.D. students, faculty and other researchers in a specific area. The Heavy-Fermions (sometimes known as Heavy-Electrons) is a loosely defined collection of intermetallic compounds containing rare-earth (mostly Ce) or actinide (mostly U) elements. These unusual names were given due to the large effective mass (100-1,000 times greater than the mass of a free electron) below a critical temperature. They have a variety of ground states including superconducting, antiferromagnetic, paramagnetic or semiconducting. Some display unusual magnetic properties such as magnetic quantum critical point and metamagnetism. This book is essentially a summary as well as a critical review of the theoretical and experimental work done on Heavy Fermions. · Extensive research references. · Comprehensive review of a very rapidly growing number of theories. · Summary of all important experiments. · Comparison with other highly correlated systems such as High-Tc Superconductors. · Possible Technological applications.

Magnetism in Heavy Fermion Systems is a review volume which covers an important subset of topics in the field of heavy fermion and non-Fermi liquid physics. It summarizes much of the experimental information in these areas, and includes an article which discusses theoretical interpretations of the complex magnetic behavior of heavy fermion systems. The topics covered include heavy fermion superconductivity, muon spin relaxation in small-moment heavy fermions, neutron scattering from heavy fermions, random localized magnetism in heavy fermions, and magnetism in Pr-containing cuprates. One feature of the book which should be helpful to graduate students and new workers in the field is the extensive references and a separate list of review articles.

This book explains modern and interesting physics in heavy-fermion (HF) compounds to graduate students and researchers in condensed matter physics. It presents a theory of heavy-fermion (HF) compounds such as HF metals, quantum spin liquids, quasicrystals and two-dimensional Fermi systems. The basic low-temperature properties and the scaling behavior of the compounds are described within the framework of the theory of fermion condensation quantum phase transition (FCQPT). Upon reading the book, the reader finds that HF compounds with quite different microscopic nature exhibit the same non-Fermi liquid behavior, while the data collected on very different HF systems have a universal scaling behavior, and these compounds are unexpectedly uniform despite their diversity. For the reader's convenience, the analysis of compounds is carried out in the context of salient experimental results. The numerous calculations of the non-Fermi liquid behavior, thermodynamic, relaxation and transport properties, being in good agreement with experimental facts, offer the reader solid grounds to learn the theory's applications. Finally, the reader will learn that FCQPT develops unexpectedly simple, yet completely good description of HF compounds.

The behaviour of magnetic impurities in metals has posed problems to challenge the condensed matter theorist over the past 30 years. This book deals with the concepts and techniques which have been developed to meet this challenge, and with their application to the interpretation of experiments. This book will be of interest to condensed matter physicists, particularly those interested in strong correlation problems. The detailed discussions of advanced many-body techniques should make it of interest to theoretical physicists in general.

The story of heavy fermions (HF) begun with the discovery of the low temperature behaviour of CeAl3 by Andres et al. in the year 1975 took the momentum after the discovery of superconductivity in CeCu2Si2 by Steglich et al. in the year 1979 . Though HF behaviour is common in the rare-earth elements like Ce, Yb and actinides like U, it is also found to exist in some of the praseodymium (Pr), samarium (Sm) , plutonium (Pu) and more recently in neptunium (Np) systems. These compounds are characterized by the presence of partially filled f-electron bands. At high temperatures, these magnetic moments manifest themselves as a weakly interacting set of local moments of the f electrons with Curie-Weiss susceptibility that coexists with light s or d conduction electrons. But at low temperature, these f-electrons hybridize with conduction electrons near Fermi level via Kondo spin fluctuation which happens through constant exchange spin-flip transition of f-electrons and band electrons in the vicinity of Fermi level. This process leads to a strong mixing of Fermi electrons with the localized f-electrons which is manifested in a renormalization of the Fermi surface and a drastic enhancement of the effective mass of the electrons at Fermi level. Further, in HF systems, electron-phonon interaction (EPI) contributes a lot in manifestation of some of the anomalous behaviour relating to elastic constant, ultrasonic attenuation & sound velocity, anisotropic Fermi surface, Kondo volume collapse etc. In this PhD thesis book in title “Electron phonon interaction and its effect in heavy fermion (HF) systems” the author tries to put some light into the behavoiour of Electron-phonon interaction in describing some of the properties of HF systems at low temperatures. In this 1 st edition, the book has been presented in multicolour edition with profuse colour illustrations so as to increase its clarity, understand ability and legibility, especially of the figures depicted to explain the low temperature behaviour of HF systems. It is hoped that the present book will serve its purpose in attracting young researchers to the field of HF systems. It is my foremost duty to express my deep sense of gratitute to my supervisor Dr. Pratibindhya Nayak , Professor Emeritus, School of Physics, Sambalpur University, Odisha, for his able guidance at every stage of this work.. His innovative methods and inspirational guidance have largely contributed to the conceptualization of the form and content of this book. I am indebted to my family members for their constant support. I am sincerely thankful to the publisher, Newredmars Education to bring my works into light in form of a book Healthy criticism and suggestions for further improvement of the book are solicited.

The Landau Institute for Theoretical Physics was created in 1965 by a group of LD Landau's pupils. Very soon, it was widely recognized as one of the world's leading centers in theoretical physics. According to Science Magazine, the Institute in the eighties had the highest citation index among all the scientific organizations in the former Soviet Union. This collection of the best papers of the Institute reflects the development of the many directions in the exact sciences during the last 30 years. The reader can find the original formulations of well-known notions in condensed matter theory, quantum field theory, mathematical physics and astrophysics, which were introduced by members of the Landau Institute.The following are some of the achievements described in this book: monopoles (A Polyakov), instantons (A Belavin et al.), weak crystallization (S Brazovskii), spin superfluidity (I Fomin), finite band potentials (S Novikov) and paraconductivity (A Larkin, L Aslamasov).

During the Koln meeting (August 28-31, 1984), Irdia was chosen as the venue for the next International Conference on Valence Fluctuations. lhis was in recognition ard appreciation of the work done, both experimental ard theoretical, by the Irdian scientists in this area during the last decade. We decided to hold this Conference in the month of January, 1987 at Bangalore. lhe subject of Valence Fluctuations has kept itself alive ard active as it has provided many shocks ard suprises particularly among the Ce- ard U-based intermetallies. lhe richness of many interesting physical phenomena occurring in mixed valent materials, the flexibility of modifying their physical properties (by alloying, for example) ard the possibility of synthesizing a wide variety of new such materials seem to be the key factors in this regard. Barely six months before this Conference, an International Conference on Anomalous Rare Earths and Actinides (ICAREA) had been held at Grenoble (July, 1986) which also focussed on mixed valence ard heavy fermion phenomena. In spite of this, the response to this' Conference was very enthusiastic and encouraging. Many interesting ard important results were presented at this Conference which have been included in this volume.