Searching Majorana modes in various topological superconductors

Abstract

The localized Majorana mode, an electronic condensed matter quasiparticle excitation, represents a possible candidate to resolve the decoherence-intolerant problem faced by conventional quantum computers. It is the core subject of study in this work. This work searches for localized Majorana modes in various topological superconductors, including Bi₂Te_3/Fe_1+yTe nanowire/nanoribbons, an Sb₂Te_3/Fe_1+yTe nanoribbon, a Nb/Quantum Anomalous Hall Insulator (Nb/QAHI) nanocut, a 2D MoSe₂/NbSe₂/MoSe₂ heterostructure, as well as a 2D MnTe/Mo₂C-Mo₂C heterostructure. The theories on how these devices can host localized Majorana modes will be introduced first, followed by the experimental results from devices fabricated from these heterostructures. Experimental evidence suggests the possible existence of localized Majorana mode in Bi₂Te_3/Fe_1+yTe nanowire/nanoribbons, the 2D MoSe₂/NbSe₂/MoSe₂ heterostructure and 2D MnTe/Mo₂C-Mo₂C heterostructure. In addition, unconventional superconductivity is demonstrated in the Sb₂Te_3/Fe_1+yTe nanoribbon as well as the 2D MnTe/Mo₂C-Mo₂C heterostructure. However, the theoretically predicted signature of a localized Majorana mode in Nb/QAHI nanocut was not observed.

Date of Award	2023
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Rolf Walter LORTZ (Supervisor)