Absence of proximity induced superconductivity in Bi/Bi2212 heterostructure

Mixing of topological states with superconductivity could result in topological superconductivity, where the elusive Majorana fermions could be applied in fault-tolerant quantum computing. Recent study⁽¹⁾ suggests that topological superconductivity might be possible to realize in a Bi /Bi₂Sr₂CaCu₂O_8+δ (Bi2212) heterostructure by inducing a pairing in the Rashba-spin−orbit-coupled states of Bi by proximity effect. Here, we present an angle-resolved photoemission spectroscopy study of ultrathin Bi films grown in-situ on Bi2212 that show the absence of proximity effect. We find that the electron transfer from the film to the substrate and the resulting severe underdoping of Bi2212 interface is a likely origin for the absence of proximity effect. We also propose a possible way of preventing a total loss of proximity effect in this system.
(1) Shimamura et al., ACS Nano 12, 10977−10983 (2018).