论文标题
无节性拓扑超导体中超流体密度的非常规压力依赖性$α$ -pdbi $ _2 $
Unconventional pressure dependence of the superfluid density in the nodeless topological superconductor $α$-PdBi$_2$
论文作者
论文摘要
我们使用MUON自旋旋转（$ $ $ SR）实验研究了拓扑超导体$α$ -PDBI $ _2 $的超导性能，外部压力高达1.77 〜GPA。环境压力测量值证明了大部分标本中的完全间隙的$ s $波超导状态。 AC磁化敏感性和$μ$ SR的测量结果表现出$ t _ {\ rm c} $的连续抑制。同时，我们观察到施加外部压力后，超级流体密度显着降低了$ \ sim $ 20 \％。值得注意的是，超流体密度遵循$ t _ {\ rm c} $线性关系，这是在一些非常规的拓扑超导体和孔掺杂的蛋糕中发现的。这一发现标志着从$α$ - pdbi $ _2 $中的BEC到BCS的可能交叉。
We investigated the superconducting properties of the topological superconductor $α$--PdBi$_2$ at ambient and external pressures up to 1.77~GPa using muon spin rotation ($μ$SR) experiments. The ambient pressure measurements evince a fully gapped $s$-wave superconducting state in the bulk of the specimen. AC magnetic susceptibility and $μ$SR measurements manifest a continuous suppression of $T_{\rm c}$ with increasing pressure. In parallel, we observed a significant decrease of superfluid density by $\sim$20\% upon application of external pressure. Remarkably, the superfluid density follows linear relation with $T_{\rm c}$ which was found before in some unconventional topological superconductors and hole doped cuprates. This finding signals a possible crossover from BEC to BCS in $α$--PdBi$_2$.
