Impurity scattering in a superconductor may serve as an important probe for the nature of superconducting pairing state. Here we re- port the impurity effect on superconducting transition temperature Te in the newly d...Impurity scattering in a superconductor may serve as an important probe for the nature of superconducting pairing state. Here we re- port the impurity effect on superconducting transition temperature Te in the newly discovered Cr-based superconductor K2Cr3As3. The resistivity measurements show that the crystals prepared using high-purity Cr metal （≥99.99%） have an electron mean free path much larger than the superconducting coherence length. For the crystals prepared using impure Cr that contains various non- magnetic impurities, however, the Tc decreases significantly, in accordance with the generalized Abrikosov-Gor＇kov pair-breaking theory. This finding supports a non-s-wave superconductivity in K2Cr3As3.展开更多
One of the most strikingly universal features of the high-temperature superconductors is that the super- conducting phase emerges in the close proximity of the antiferromagnetic phase, and the interplay between these ...One of the most strikingly universal features of the high-temperature superconductors is that the super- conducting phase emerges in the close proximity of the antiferromagnetic phase, and the interplay between these two phases poses a long-standing challenge. It is commonly believed that, as the antifer- romagnetic transition temperature is continuously suppressed to zero, there appears a quantum critical point, around which the existence of antiferromagnetic fluctuation is responsible for the development of the superconductivity. In contrast to this scenario, we report the observation of a bi-critical point identified at 2,88 GPa and 26.02 K in the pressurized high-quality single crystal Cao.73Lao.27FeAs2 by com- plementary in-situ high pressure measurements. At the critical pressure, we find that the antiferromag- netism suddenly disappears and superconductivity simultaneously emerges at almost the same temperature, and that the external magnetic field suppresses the superconducting transition temperature but hardly affects the antiferromagnetic transition temperature.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 11190023)the National Basic Research Program (Grant Nos. 2011CBA00103 and 2012CB927404)the Fundamental Research Funds for the Central Universities of China
文摘Impurity scattering in a superconductor may serve as an important probe for the nature of superconducting pairing state. Here we re- port the impurity effect on superconducting transition temperature Te in the newly discovered Cr-based superconductor K2Cr3As3. The resistivity measurements show that the crystals prepared using high-purity Cr metal （≥99.99%） have an electron mean free path much larger than the superconducting coherence length. For the crystals prepared using impure Cr that contains various non- magnetic impurities, however, the Tc decreases significantly, in accordance with the generalized Abrikosov-Gor＇kov pair-breaking theory. This finding supports a non-s-wave superconductivity in K2Cr3As3.
基金supported by the National Natural Science Foundation of China(91321207,11427805,U1532267,11404384)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB07020300)+2 种基金the National Key Research and Development Program of China(2016YFA0300300)the Russian Foundation for Basic Research(15-02-02040)the U.S.NSF DMREF(DMR-1435672)
文摘One of the most strikingly universal features of the high-temperature superconductors is that the super- conducting phase emerges in the close proximity of the antiferromagnetic phase, and the interplay between these two phases poses a long-standing challenge. It is commonly believed that, as the antifer- romagnetic transition temperature is continuously suppressed to zero, there appears a quantum critical point, around which the existence of antiferromagnetic fluctuation is responsible for the development of the superconductivity. In contrast to this scenario, we report the observation of a bi-critical point identified at 2,88 GPa and 26.02 K in the pressurized high-quality single crystal Cao.73Lao.27FeAs2 by com- plementary in-situ high pressure measurements. At the critical pressure, we find that the antiferromag- netism suddenly disappears and superconductivity simultaneously emerges at almost the same temperature, and that the external magnetic field suppresses the superconducting transition temperature but hardly affects the antiferromagnetic transition temperature.
