Calorimetric evidence of nodal gaps in the nematic superconductor FeSe
Calorimetric evidence of nodal gaps in the nematic superconductor FeSe
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DOI：
10.1103/physrevb.99.035157
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发表时间：
2018-07
影响因子：
3.7
通讯作者：
F. Hardy;M. He;Liran Wang;Thomas Wolf;P. Schweiss;M. Merz;Maik Barth;P. Adelmann;R. Eder;A. Haghighirad;C. Meingast
中科院分区：
文献类型：
--
作者：
F. Hardy;M. He;Liran Wang;Thomas Wolf;P. Schweiss;M. Merz;Maik Barth;P. Adelmann;R. Eder;A. Haghighirad;C. Meingast
FeSe的超导电性最近引起了人们极大的关注，因为它是从一种难以捉摸的电子超导电态中产生的。在这里，我们研究了电子正常状态和超导间隙结构使用高品质的单晶热容测量。从0.4 K到Tc = 9.1 K的比热曲线与最近用Bogoliubov准粒子干涉法测定的能隙一致。Sprau等人，Science 357，75（2017）]，然而，只有当节点被引入到电子或空穴费米表面片上时。我们的分析与量子振荡测量一致，只依赖于两个带的存在，因此理论上预测的第二个电子口袋的命运仍然是神秘的。
Superconductivity in FeSe has recently attracted a great deal of attention because it emerges out of an electronic nematic state of elusive character. Here we study both the electronic normal state and the superconducting gap structure using heat-capacity measurements on high-quality single crystals. The specific-heat curve, from 0.4 K to Tc = 9.1 K, is found to be consistent with a recent gap determination using Bogoliubov quasiparticle interference [P. O. Sprau et al., Science 357, 75 (2017)], however only if nodes are introduced on either the electron or the hole Fermi-surface sheets. Our analysis, which is consistent with quantum-oscillation measurements, relies on the presence of only two bands, and thus the fate of the theoretically predicted second electron pocket remains mysterious.