Deficiency of the scaling collapse as an indicator of a superconductor-insulator quantum phase transition
Deficiency of the scaling collapse as an indicator of a superconductor-insulator quantum phase transition
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DOI：
10.1103/physrevb.101.235164
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发表时间：
2020-03
影响因子：
3.7
通讯作者：
A. Rogachev;B. Sac'ep'e
中科院分区：
文献类型：
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作者：
A. Rogachev;B. Sac'ep'e
量子尺寸标度分析是一种被广泛接受的方法，用于识别和表征超导、磁性和绝缘系统中的量子相变（QPT）。我们正式应用这种分析的形式适合于QPT在2维超导薄膜磁场驱动的超导金属过渡在1维钼锗纳米线。尽管显然不适用于纳米线，二维缩放方程导致高质量的缩放崩溃的纳米线电阻的温度和电阻范围内的可比性或更好的是在膜的分析中接受的。我们的研究结果表明，外观和质量的缩放崩溃本身是不是一个可靠的指标QPT。我们还观察到了零偏异常（ZBA）的符号变化的非线性电阻，发生在临界场的意外QPT。这种行为通常被认为是对过渡的额外确认。我们认为，在纳米线，非线性是由电子加热，并没有关系的临界波动。我们的观察表明，类似于标度崩溃，ZBA的符号变化可能是QPT的误导性指标。
Finite-size scaling analysis is a well-accepted method for identification and characterization of quantum phase transitions (QPTs) in superconducting, magnetic and insulating systems. We formally apply this analysis in the form suitable for QPTs in 2-dimensional superconducting films to magnetic-field driven superconductor-metal transition in 1-dimensional MoGe nanowires. Despite being obviously inapplicable to nanowires, the 2d scaling equation leads to a high-quality scaling collapse of the nanowire resistance in the temperature and resistance ranges comparable or better to what is accepted in the analysis of the films. Our results suggest that the appearance and the quality of the scaling collapse by itself is not a reliable indicator of a QPT. We have also observed a sign-change of the zero-bias anomaly (ZBA) in the non-linear resistance, occurring exactly at the critical field of the accidental QPT. This behavior is often taken as an additional confirmation of the transition. We argue that in nanowires, the non-linearity is caused by electron heating and has no relation to the critical fluctuations. Our observation suggests that similar to the scaling collapse, the sign-change of ZBA can be a misleading indicator of QPT.