论文标题
缩放塌陷的不足是超导体量子量子相变的指标
Deficiency of the scaling collapse as an indicator of a superconductor-insulator quantum phase transition
论文作者
论文摘要
有限大小的缩放分析是一种鉴定和表征超导，磁性和绝缘系统中量子相变（QPTS）的良好方法。我们以适用于二维超导膜中QPT的形式正式应用此分析，以在1维MOGE纳米线中的磁场驱动的超导体 - 金属转变。尽管显然对纳米线不适用，但2D缩放方程式导致温度下的纳米电阻的高质量缩放崩溃和耐药性范围与对膜分析中所接受的相当或更好。我们的结果表明，缩放量崩溃的外观和质量本身并不是QPT的可靠指标。我们还观察到非线性电阻的零偏置异常（ZBA）的标志变换，正好发生在意外QPT的临界场上。这种行为通常被视为过渡的附加确认。我们认为，在纳米线中，非线性是由电子加热引起的，与临界波动无关。我们的观察结果表明，与缩放崩溃相似，ZBA的签名变换可能是QPT的误导指标。
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.
