论文标题
各向异性超导体的异常间隙比：压力下的铝
Anomalous gap ratio in anisotropic superconductors: aluminum under pressure
论文作者
论文摘要
元素铝在元素铝中热力学临界场$ b _ {\ mathrm {c}} $的压力依赖性通过muon-spin旋转/放松技术研究。压力增强了$ b _ {\ mathrm {c}}（t）$的偏差，从抛物面行为中，预期对于典型的I型超导体，这表明间隙比$ \langleα\langleα\ rangle = \ langle = \langleδ } t _ {\ Mathrm {c}} $（$ \langleδ\ rangle $是超导能量差距的平均值，$ t _ {\ mathrm {c}} $是过渡温度和$ k _ {\ kathrm {b Mathrm {b {b {b} $ boltzmann常数。随着压力从0.0增加到$ \ simeq1.6 $ gpa，$ \langleα\ rangle $ $从1.73降低至1.67。因此，我们的结果表明，在元素铝中，间隙比$ \langleα\ rangle $小于弱耦合的BCS预测$α_ {\ MATHRM {bcs}} \ simeq1.764 $，并且在压力下甚至会进一步降低。
Pressure dependence of the thermodynamic critical field $B_{\mathrm{c}}$ in elemental aluminum was studied by means of the muon-spin rotation/relaxation technique. Pressure enhances the deviation of $B_{\mathrm{c}}(T)$ from the parabolic behavior, expected for a typical type-I superconductor, thus suggesting the weakening of the gap ratio $\langleα\rangle=\langle Δ\rangle/k_{\mathrm{B} }T_{\mathrm{c}}$ ($\langleΔ\rangle$ is the average value of the superconducting energy gap, $T_{\mathrm{c}}$ is the transition temperature and $k_{\mathrm{B}}$ is the Boltzmann constant). With the pressure increase from 0.0 to $\simeq1.6$ GPa, $\langleα\rangle$ decreases almost linearly from 1.73 to 1.67. Our results imply, therefore, that in elemental aluminum the gap ratio $\langleα\rangle$ is smaller than the weak-coupled BCS prediction $α_{\mathrm{BCS}}\simeq1.764$ and it is even further reduced under pressure.
