Qin Jin, Zhao Chenxiao, Xia Bing, Wang Zerui, Liu Yu, Guan Dandan, Wang Shiyong, Li Yaoyi, Zheng Hao, Liu Canhua, Jia Jinfeng
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
Nanotechnology. 2020 Jul 24;31(30):305708. doi: 10.1088/1361-6528/ab8763. Epub 2020 Apr 7.
Low dimensional superconductors have many unusual properties. When 0-dimensional superconductors reach the nanometer scale, the superconducting energy gap can be enhanced due to the shell effect. At the same time, the single electron Coulomb blockade effect can also be observed on metal nanoparticles if they are weakly coupled to the environment. So, if a superconducting nanoparticle is isolated well from the environment, the superconducting gap and the Coulomb gap would couple together, making the tunneling spectrum more complicated and interesting. Here Sn nanoparticles were deposited on the surface of STO (111). The charging energy of a nanoparticle mainly depends on its size and is comparable to the superconducting gap when the isolated particle is large enough. The superconducting energy gap can be deduced from the coupling tunneling spectrum and the shell effect is observed. The method to deduce the superconducting gap here is simpler than when fit using the Dynes density of states. Owing to the increased superconducting gap and critical field, the studied nanoparticles may find applications in studies of the properties of Majorana fermions.
低维超导体具有许多不寻常的特性。当零维超导体达到纳米尺度时，由于壳层效应，超导能隙会增强。同时，如果金属纳米颗粒与环境弱耦合，在其上也能观察到单电子库仑阻塞效应。因此，如果一个超导纳米颗粒与环境很好地隔离，超导能隙和库仑能隙会耦合在一起，使得隧穿谱更加复杂和有趣。这里，锡纳米颗粒沉积在STO(111)表面。纳米颗粒的充电能量主要取决于其尺寸，当孤立颗粒足够大时，充电能量与超导能隙相当。超导能隙可从耦合隧穿谱中推导出来，并且观察到了壳层效应。这里推导超导能隙的方法比使用戴恩斯态密度进行拟合时更简单。由于超导能隙和临界场的增加，所研究的纳米颗粒可能在马约拉纳费米子性质的研究中找到应用。
