A Theory of Anisotropic Semiconductor of Heavy Fermions

概要

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It is demonstrated that a k-dependence of the hybridization matrix element between J- andconduction electrons can give rise to an anisotropic hybridization gap of heavy fermions if thefilling of electrons corresponds to that of the band insulator. The rnost interesting case occurswhen the hybridization vanishes along some symmetry axis of' the crystal reflecting a particularsymmetry of the crystal field. The results of a model calculation are consistent with wide rangeof anomalous properties observed in CelNiSn and its isostrtrctural cornpotrnds, the anisotropicsemiconductor of heavy fermions. In particular, highly sernsitive effect of impurity scatteringon the residual density of states for zero energy excitation and the anisotropic temperaturedependence of the resistivity are well explained. It is also discussed that a weak semirnetallicbehavior arises through the weak k-dependence of the /-electron self-energy ,U.7(k, O).
社団法人日本物理学会の論文
1996-06-15