Interfacial Superconductivity and Zero Bias Peak in Quasi‐One‐Dimensional Bi2Te3/Fe1+yTe Heterostructure Nanostructures. (14th February 2023)

• Record Type: Journal Article
• Authors: Cheng, Man Kit; Ng, Cheuk Yin; Ho, Sui Lun; Atanov, Omargeldi; Tai, Wai Ting; Liang, Jing; Lortz, Rolf; Sou, Iam Keong
• Is Part Of: Advanced Electronic Materials. Volume 9:Number 4(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-02-14
• Subjects: Andreev reflection point contact spectroscopy -- interfacial superconductivity -- Majorana zero modes -- quasi‐one‐dimensional superconductivity -- topological superconductivity; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.202200943
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract: Bismuth telluride/iron telluride (Bi2 Te3 /Fe1+y Te) heterostructures are known to exhibit interfacial superconductivity between two non‐superconducting materials: Fe1+y Te as the parent compound of Fe‐based superconducting materials and the topological insulator Bi2 Te3 . Here, a top‐down approach is presented starting from 2D heterostructures to fabricate 1D Bi2 Te3 /Fe1+y Te nanowires or narrow nanoribbons. It is demonstrated that the Bi2 Te3 /Fe1+y Te heterostructure remains intact in nanostructures of widths on the order of 100 nm and the interfacial superconductivity is preserved, as evidenced by electrical transport and Andreev reflection point contact spectroscopy experiments measured at the end of the nanowire. The differential conductance shows a similar superconducting twin‐gap structure as in 2D heterostructures, but with enhanced fluctuation effects due to the lower dimensionality. A zero‐bias conductance peak indicates the presence of an Andreev bound state and, given the involvement of the topological Bi2 Te3 surface state, a possible topological nature of superconductivity is discussed with strong interplay with an emerging ferromagnetism due to the interstitial excess iron (Fe) in the Fe1+y Te layer, developing in parallel with superconductivity at low temperatures. Abstract : Bi2 Te3 /Fe1+y Te heterostructures show interfacial superconductivity between two non‐superconducting materials. A top‐down approach is presented to fabricate 1D Bi2 Te3 /Fe1+y Te nanoribbons with integrated tunnel junctions, which show an Andreev‐bound state that appears to be driven into the region of topological superconductivity by a parallel magnetic field.