arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1902.04797cond-mat.supr-con
收藏

旋转磁场中$\mathrm{CeCoIn_5}$自旋密度波与可能的Fulde-Ferrell-Larkin-Ovchinnikov态的相互作用

Interplay of the spin density wave and a possible Fulde-Ferrell-Larkin-Ovchinnikov state in $\mathrm{CeCoIn_5}$ in rotating magnetic field

Shi-Zeng Lin, Duk Y. Kim, Eric D. Bauer, Filip Ronning, J. D. Thompson, Roman Movshovich

备注：
5 pages and 4 figures
发表信息：
Phys. Rev. Lett. 124, 217001 (2020)
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

$d$波超导体$\mathrm{CeCoIn_5}$被认为是在其上临界场的低温边界附近支持Fulde-Ferrell-Larkin-Ovchinnikov（FFLO）态的强有力的候选者。然而，中子衍射发现，在$a$ - $b$平面中的场的相图的这一部分中，存在自旋密度波（SDW）序，并且当所施加的场朝向四重$c$轴旋转时，SDW的证据消失。理解SDW和$\mathrm{CeCoIn_5}$中可能的FFLO状态之间的相互作用是很重要的，因为仅仅存在SDW并不一定排除FFLO状态。在这里，基于现有实验的基础上构建的模型，我们表明，FFLO状态与SDW相竞争。当磁场指向接近$a$ - $b$平面时，$\mathrm{CeCoIn_5}$中的SDW状态稳定。当磁场向$c$轴旋转时，出现FFLO状态，SDW相位消失。在FFLO态中，具有额外准粒子的节面（其中超导序参量为零）垂直于场，并且在SDW相中，准粒子态密度减小。我们通过测量超导状态下正常准粒子的热传输来测试这个模型的预测。作为场的函数，我们观察到接近于$a$ - $b$平面的场的热导率的降低和接近于$c$轴的场的热导率的增强，与理论预期一致。因此，我们的模拟和实验表明，当场平行于$c$轴时，FFLO态的存在。

英文摘要：

The $d$-wave superconductor $\mathrm{CeCoIn_5}$ has been proposed as a strong candidate for supporting the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state near the low-temperature boundary of its upper critical field. Neutron diffraction, however, finds spin-density-wave (SDW) order in this part of the phase diagram for field in the $a$-$b$ plane, and evidence for the SDW disappears as the applied field is rotated toward the tetragonal $c$ axis. It is important to understand the interplay between the SDW and a possible FFLO state in $\mathrm{CeCoIn_5}$, as the mere existence of an SDW does not necessary exclude an FFLO state. Here, based on a model constructed on the basis of available experiments, we show that an FFLO state competes with an SDW phase. The SDW state in $\mathrm{CeCoIn_5}$ is stabilized when the field is directed close to the $a$-$b$ plane. When the field is rotated toward the $c$ axis, the FFLO state emerges, and the SDW phase disappears. In the FFLO state, the nodal planes with extra quasiparticles (where the superconducting order parameter is zero) are perpendicular to the field, and in the SDW phase, the quasiparticle density of states is reduced. We test this model prediction by measuring heat transported by normal quasiparticles in the superconducting state. As a function of field, we observe a reduction of thermal conductivity for field close to the $a$-$b$ plane and an enhancement of thermal conductivity when field is close to the $c$ axis, consistent with theoretical expectations. Our modeling and experiments, therefore, indicate the existence of the FFLO state when field is parallel to the $c$ axis.

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。

↑