Impurity-induced gap renormalization in anisotropic superconductors: Mixed-state specific heat of La2−xSrx(Cu1−yZny)O4 and Y(Ni1−xPtx)2B2C
2000; Elsevier BV; Volume: 341-348; Linguagem: Inglês
10.1016/s0921-4534(00)01259-4
ISSN1873-2143
AutoresM. Nohara, Hiroaki Suzuki, N. Mangkorntong, H. Takagi,
Tópico(s)Rare-earth and actinide compounds
ResumoThe effect of nonmagnetic impurity on the superconducting gap is examined on La2−xSrx(Cu1−yZny)O4 and Y(Ni1−xPtx)2B2C from the T and H dependence of the electronic specific heat Ce(T, H) at low temperatures. In La2−xSrxCuO4, impurity scattering leads to an appearance of a finite density of states (DOS) at the Fermi energy, consistent with d-wave pairing state with nonmagnetic impurity scattering in the unitarity limit. In contrast, nonmagnetic impurity scattering in YNi2B2C leads to a smearing of the gap anisotropy and the opening of a gap in the DOS over the whole Fermi surface, though Ce(T, H) for pure compound suggests the presence of anisotropic gap. This indicates YNi2B2C is a highly anisotropic s-wave superconductor.
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