Observation of a crossover from nodal to gapped superconductivity in LuxZr1-xB12

Article

关键词: UNCONVENTIONAL SUPERCONDUCTORS;    CRYSTAL-STRUCTURE;    SINGLE-CRYSTALS;    KNIGHT SHIFT;    ZRB12;    LUB12;    RESONANCE;    BORON;    FIELD;    DODECABORIDES;   

DOI  :  10.1103/PhysRevB.98.094505

来源: SCIE

【 摘 要 】

We have determined the superconducting and magnetic properties of four samples of LuxZr1-xB12 (x = 0.04, 0.07, 0.17, and 0.8) using muon spin rotation (mu SR) and magnetometry measurements. We observed a strong magnetic signal in both the mu SR and magnetometry data in one sample (x = 0.07), likely caused by the formation of static moments of size approximate to 1 mu(B) due to a clustering effect of the Lu3+ ions. In all other samples, we find only a small magnetic signal in the mu SR data thought to originate from boron nuclei in the B-12 cages. The superconductivity is found to evolve with x, with a decrease in x resulting in an increase in critical temperature and a decrease of the penetration depth. Most remarkably, we find the formation of nodes in the superconducting gap for x <= 0.17, providing a new example of an s-to-s + d-wave crossover in a superconductor.

【 授权许可】

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