论文标题
cerh $ _2 $ as $ _2 $中的野外依赖揭示了奇数超导性
Field-angle dependence reveals odd-parity superconductivity in CeRh$_2$As$_2$
论文作者
论文摘要
CERH $ _2 $ AS $ _2 $是一种非常规的超导体，具有多个超导阶段和$ t_ \ mathrm {c} = 0.26 $K。当$ h \ parallel c $ C $时，它显示了$μ_0H^* = 4 $ t scan的$μ_0H^* = 4 $ t sc2 sc2 sc2 to in field引起的过渡时， $μ_0H_\ MATHRM {C2} = 14 $T。相比之下，对于$ H \ PERP C $，仅观察到具有$μ_0H_\ Mathrm {C2} = 2 $ T的SC1。一个基于晶体对称性的简单模型能够重现相数及其各向异性，分别以均匀和奇怪的奇偶校验超导状态识别SC1和SC2。但是，在正常状态下观察到其他订单，这可能会影响$ h^*$的超导状态的变化。在这里，我们使用磁性交流敏感性，cerh $ _2 $的单晶上的特定热量和扭矩为$ _2 $，对上临界场的角度依赖性，特异性热和扭矩进行了全面研究。实验表明，在将磁场旋转到$ c $轴时，状态SC2被强烈抑制，并且它以35 $^{\ circ} $的角度消失。这种行为与我们在飞机上具有$ \ vec {d} $向量的伪s-tirep状态的扩展模型完全吻合，因此可以钉住SC2确实是建议的奇数状态。
CeRh$_2$As$_2$ is an unconventional superconductor with multiple superconducting phases and $T_\mathrm{c} = 0.26$ K. When $H\parallel c$, it shows a field-induced transition at $μ_0H^* = 4$ T from a low-field superconducting state SC1 to a high-field state SC2 with a large critical field of $μ_0H_\mathrm{c2} = 14$ T. In contrast, for $H\perp c$, only the SC1 with $μ_0H_\mathrm{c2} = 2$ T is observed. A simple model based on the crystal symmetry was able to reproduce the phase-diagrams and their anisotropy, identifying SC1 and SC2 with even and odd parity superconducting states, respectively. However, additional orders were observed in the normal state which might have an influence on the change of the superconducting state at $H^*$. Here, we present a comprehensive study of the angle dependence of the upper critical fields using magnetic ac-susceptibility, specific heat and torque on single crystals of CeRh$_2$As$_2$. The experiments show that the state SC2 is strongly suppressed when rotating the magnetic field away from the $c$ axis and it disappears for an angle of 35$^{\circ}$. This behavior agrees perfectly with our extended model of a pseudospin triplet state with $\vec{d}$ vector in the plane and hence allows to nail down that SC2 is indeed the suggested odd-parity state.
