Phisics of Strongly Correlated Conducting Elevtrons

The Theory Group of Research Project "Physics of Strongly Correlated Conducting Electrons" hascarried out研究in close collaboration with the Experiment Group. the main results during the 4years are as follows.(1) Among many f-electron superconductors UPt3 having plural superconductingphases is clearly unconventional in the nature of superconductivity. On this material Kitaoka等。al. (Osaka Univ.) and Sakakibara (Hokkaido Univ.) have carried out detailed NMR and magneticmeasurements. Machida (Okayama Univ.) has proposed a scenario of triplet superductivity to那些实验基于一个phenomenological theory，它是下一个重要问题give a microscopic origin of the superconductivity.(2)这是一个共同的魔法。impurities in metals usually turn to Fermi liquid at low temperatures. However，Sakakibara et. al. found that ThRu i D22 i D2Si i D22 i D22 i D2 containing dilute U shows non-Fermi liquidbehavior. This problem was theoretically studied by 3groups, Shiba （Tokyo Inst. Tech.）Sakai (Tohoku Univ.) and Miyake (Osaka Univ.). The results show that when The crystal field groundstate is non-Kramers doublet and well separated from excited statestwo-channel-Kondo non-Fermi liquid is possible，while it is taken over by Fermi liquid when the excited states become low. Sakai and his coworkersdetermined the temperature dependence of various physical quantities by using numericalrenormalization group method.(3) Because of orbital degrees of freedom the ordered phase of somef-electron systems are complicated. In addition to ordinary magnetic orderings one can have anordered phase related to quadrupole moments. CeB - D26 - D2 a typical example of this sort. The naturethe ordered phase in magnetic fields in particular had been a matter of controversy. Shiba andSakai studied this problem and showed that in CeB D26 the fild -induced octupoles are sizableimportant to explain the NMR shifts，which been a mystery for a long period. In this connection Kuramoto (Tohoku Univ) presented a(4) Miyake presented a theory of Kondo semiconductors，taking into account the k-dependence of mixing matrix elements. It explains良好的实验results of CeNiSn，which Takabatake (Hiroshima Univ) studied experimentally.(5) Band structure calculations have beencarried out on many rare-earth compounds by Hasegawa (Niigata Univ.) and Harima (Osaka Univ.). Theyhave brought important information on electronic structure through a comparison with de Hans- vanAlphen experiments by Onuki (Osaka Univ.). Hasegawa et. al. have develped a theory of relativistic目前，它是希望，它是成功适用于actinidecompounds . less

The Theory Group of Research Project "Physics of Strongly Correlated Conducting Electrons" has carried out research in close collaboration with the Experiment Group. The main results during the 4 years are as follows.(1) Among many f-electron superconductors UPt3 having plural superconducting phases is clearly unconventional in the nature of superconductivity. On this material Kitaoka et. al. (Osaka Univ.) and Sakakibara (Hokkaido Univ.) have carried out detailed NMR and magnetic measurements. Machida (Okayama Univ.) has proposed a scenario of triplet superconductivity to explain those experiments based on a phenomenological theory. It is the next important problem to give a microscopic origin of the superconductivity.(2) It is a common wisdom that magnetic impurities in metals usually turn to Fermi liquid at low temperatures. However, Sakakibara et. al. found that ThRuィイD22ィエD2SiィイD22ィエD2 containing dilute U shows non-Fermi liquid behavior. This problem was theoretically studied by 3 … More groups, Shiba (Tokyo Inst. Tech.), Sakai (Tohoku Univ.) and Miyake (Osaka Univ.). The results show that when the crystal field ground state is non-Kramers doublet and well separated from excited states, two-channel-Kondo non-Fermi liquid is possible, while it is taken over by Fermi liquid when the excited states become low. Sakai and his coworkers determined the temperature dependence of various physical quantities by using numerical renormalization group method.(3) Because of orbital degrees of freedom the ordered phase of some f-electron systems are complicated. In addition to ordinary magnetic orderings one can have an ordered phase related to quadrupole moments. CeBィイD26ィエD2 a typical example of this sort. The nature of the ordered phase in magnetic fields in particular had been a matter of controversy. Shiba and Sakai studied this problem and showed that in CeBィイD26ィエD2 the field-induced octupoles are sizable and important to explain the NMR shifts, which had been a mystery for a long period. In this connection Kuramoto (Tohoku Univ.) presented a theory of fluctuating quadrupoles.(4) Miyake presented a theory of Kondo semiconductors, taking into account the k-dependence of mixing matrix elements. It explains well experimental results of CeNiSn, which Takabatake (Hiroshima Univ.) studied experimentally.(5) Band structure calculations have been carried out on many rare-earth compounds by Hasegawa (Niigata Univ.) and Harima (Osaka Univ.). They have brought important information on electronic structure through a comparison with de Hans- van Alphen experiments by Onuki (Osaka Univ.). Hasegawa et. al. have develped a theory of relativistic current and spin density functional. It is hoped that it is successfully applied to actinide compounds. Less