论文标题
超导纳米线的拓扑控制相位相干性和量子波动
Topology controlled phase coherence and quantum fluctuations in superconducting nanowires
论文作者
论文摘要
金属纳米线的超导性能可能在很大程度上取决于特定的实验条件。在这里，我们考虑了一种设置，其中超导相位波动在电线内的一个点限制，并沿着任意长度$ l $的电线段的平衡超电流流。一方面，通过平滑的相位波动，另一方面通过量子相滑来确定这种结构的低温物理。零温度相图由电线横截面控制，由一个真正的超导相和两个不同的阶段组成，其中仅在较短的长度尺度下才能观察到超导性。后一个阶段表现出更强大的短尺度超导性，而另一个阶段则证明了超电流的幂律衰减，而在相对短的尺度上已经增加了$ l $。
Superconducting properties of metallic nano-wires may strongly depend on specific experimental conditions. Here we consider a setup where superconducting phase fluctuations are restricted at one point inside the wire and equilibrium supercurrent flows along the wire segment of an arbitrary length $L$. Low temperature physics of this structure is essentially determined, on one hand, by smooth phase fluctuations and, on the other hand, by quantum phase slips. The zero temperature phase diagram is controlled by the wire cross section and consists of a truly superconducting phase and two different phases where superconductivity can be observed only at shorter length scales. One of the latter phases exhibits more robust short-scale superconductivity whereas another one demonstrates a power-law decay of the supercurrent with increasing $L$ already at relatively short scales.
