报告人：Alexander A. Golubov

时 间：2025/4/2 2:00 -3:30 PM

地 点：良乡校区，理科教学楼206教室

摘要：

Noise and current measurements are key tools for studying mesoscopic systems, revealing insights beyond conductance alone. For instance, noise measurements show that transport carriers in conventional superconductors have charge 2e. The noise power also depends on junction type, distinguishing different transport processes. Existing theories focus primarily on zero temperature shot noise in tunnel junctions with conventional superconductors, where transport is carried by quasiparticles and Cooper pairs.

Here we develop a full counting statistics theory for unconventional superconductor / normal metal junctions of different types, incorporating the effect of thermal noise on the differential Fano factor, the ratio of differential noise power and conductance. In these junctions there is a third type of transport mechanism, surface Andreev bound states. Our study reveals that junctions with dispersionless surface Andreev bound states exhibit negative differential Fano factor at finite temperatures. In contrast, in the presence of dispersive surface Andreev bound states, the noise power always increases with voltage, but there are local minima in the differential noise at those voltages corresponding to the extrema of the surface Andreev bound state spectrum. For normal metals and conventional superconductors the voltage dependence of the differential Fano factor is similar in all types of junctions, including tunnel junctions and diffusive barriers. However, significant differences arise with unconventional superconductors, making distinct junction types valuable tools for identifying pairing symmetries. Our results highlight the importance of finite temperature effects in noise power measurements for potential unconventional superconductors, offering new means to determine pairing symmetries in topological superconductors.

简历：

Alexander Avraamovitch Golubov是荷兰特文特大学教授，2021年当选美国物理学会会士，是国际物理学界知名的凝聚态物理学家。Golubov教授于1983年在俄罗斯科学院固体物理研究所获得博士学位，师从诺贝尔奖得主Alexey Abrikosov教授。1990年至1991年在德国亚琛工业大学物理系担任博士后，1995年至1996年在德国于利希研究中心（FA）担任客座科学家。1997年起在荷兰特文特大学历任助理教授、副教授、教授。2013年，赢得俄罗斯政府发起的关于超导混合结构中的拓扑量子现象的巨额资助竞赛。2018年起成为“自旋科技研究”（SPINTECH）项目的欧盟合作方，该项目由欧盟“地平线2020”计划支持，致力于设计和生产超导自旋阀的先进技术。Golubov教授长期致力于超导器件中的电子输运理论，对新型超导材料和混合结构中的约瑟夫森效应理论以及多带超导理论做出了重要贡献。特别是在超导体与半导体和铁磁纳米线接触的拓扑量子现象研究领域获得世界一流的科学成果。Golubov教授在顶级期刊上发表超过400篇文章，引用次数12000余次，h因子54。

联系方式：

邀请人： 李家方

网 址：http:/

承办单位：物理学院、先进光电量子结构设计与测量教育部重点实验室