Controllable spin-orbit coupling and its influence on the upper critical field in the chemically doped quasi-one-dimensionalNb2PdS5superconductor
Controllable spin-orbit coupling and its influence on the upper critical field in the chemically doped quasi-one-dimensionalNb2PdS5superconductor
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DOI：
10.1103/physrevb.90.094520
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发表时间：
2014-09
影响因子：
3.7
通讯作者：
N. Zhou;Xiaofeng Xu;J. R. Wang;J. H. Yang;Y. K. Li;Y. Guo;W. Yang;C. Niu;Bin Chen;C. Cao;J. Dai
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文献类型：
--
作者：
N. Zhou;Xiaofeng Xu;J. R. Wang;J. H. Yang;Y. K. Li;Y. Guo;W. Yang;C. Niu;Bin Chen;C. Cao;J. Dai
通过对新发现的超导体Nb 2 PdS 5（Tc 6 K）中Pt和Ni的系统化学替代，研究了其超导性质随掺杂的演变，重点研究了上临界场Hc 2的行为.与之前在S位上掺杂Se的结果相反，发现一维Pd链上的Pt和Ni掺杂剂的超导电性相当稳健。最引人注目的是，降低的$H_{c2}$，即，H_{c2}/T_c$的比值被较重的Pt掺杂显著提高，而在Ni掺杂的对应物中被抑制，与Se掺杂的样品中的几乎恒定的值不同。因此，我们的研究结果表明，该系统的上临界场可以修改在一个可调的方式通过化学掺杂的Pd链与不同质量数的元素。由此推断，Pd位上的自旋-轨道耦合应该在所观察到的超导性和泡利对破缺场之外的大的上临界场中起重要作用。
By systematic chemical substitution of Pt and Ni in the newly-discovered superconductor Nb$_2$PdS$_5$ ($T_c\sim$6 K), we study the evolution of its superconducting properties with doping, focussing on the behavior of the upper critical field $H_{c2}$. In contrast to the previous results of Se doping on S sites, superconductivity is found to be rather robust against the Pt and Ni dopants on the one-dimensional Pd chains. Most strikingly, the reduced $H_{c2}$, i.e., the ratio of $H_{c2}/T_c$, is seen to be significantly enhanced by the heavier Pt doping but suppressed in the Ni-doped counterparts, distinct from the nearly constant value in the Se doped samples. Our findings therefore suggest that the upper critical field of this system can be modified in a tunable fashion by chemical doping on the Pd chains with elements of varying mass numbers. The spin-orbit coupling on the Pd sites, by inference, should play an important role in the observed superconductivity and on the large upper critical field beyond the Pauli pair-breaking field.