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arXiv 1903.02410cond-mat.str-elcond-mat.supr-con
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重费米子UTe2中的非常规超导电性

Unconventional Superconductivity in Heavy Fermion UTe2

Dai Aoki, Ai Nakamura, Fuminori Honda, DeXin Li, Yoshiya Homma, Yusei Shimizu, Yoshiki J. Sato, Georg Knebel, Jean-Pascal Brison, Alexandre Pourret, Daniel Brai… 展开作者

Dai Aoki, Ai Nakamura, Fuminori Honda, DeXin Li, Yoshiya Homma, Yusei Shimizu, Yoshiki J. Sato, Georg Knebel, Jean-Pascal Brison, Alexandre Pourret, Daniel Braithwaite, Gerard Lapertot, Qun Niu, Michal Valiska, Hisatomo Harima, Jacques Flouquet

摘要:

我们生长了最近发现的重费米子超导体UTe 2的单晶,并测量了其电阻率、比热和磁阻。在RRR=35的高质量样品中,当Tsc=1.65K时,随着电阻率的急剧下降,超导性(SC)被清楚地检测到。比热在Tsc处显示出大的跳跃,表明强耦合。大的索末菲系数,117 mJ K-2 mol-1外推在正常状态和温度依赖性的C/T低于Tsc的非常规SC的签名。SC和正常状态之间的Tsc的熵平衡的差异指出,隐藏的功能必须发生。令人惊讶的是,索末菲系数的大残差值似乎相当稳健(gamma_0/gamma ~ 0.5)。沿三个主轴的大的上临界场Hc 2有利于自旋三重态SC。对于H //b轴,我们的实验没有重现以前报道的Hc 2的巨大的上转。这种差异可能反映了Hc 2对样品质量非常敏感。一个新的视角在UTe 2是近藤半导体相预测的LDA能带结构计算的接近。

英文摘要:

We grew single crystals of the recently discovered heavy fermion superconductor UTe2, and measured the resistivity, specific heat and magnetoresistance. Superconductivity (SC) was clearly detected at Tsc=1.65K as sharp drop of the resistivity in a high quality sample of RRR=35. The specific heat shows a large jump at Tsc indicating strong coupling. The large Sommerfeld coefficient, 117mJ K-2mol-1 extrapolated in the normal state and the temperature dependence of C/T below Tsc are the signature of unconventional SC. The discrepancy in the entropy balance at Tsc between SC and normal states points out that hidden features must occur. Surprisingly, a large residual value of the Sommerfeld coefficient seems quite robust (gamma_0/gamma ~ 0.5). The large upper critical field Hc2 along the three principal axes favors spin-triplet SC. For H // b-axis, our experiments do not reproduce the huge upturn of Hc2 reported previously. This discrepancy may reflect that Hc2 is very sensitive to the sample quality. A new perspective in UTe2 is the proximity of a Kondo semiconducting phase predicted by the LDA band structure calculations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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