Materials for Majorana-based Topological Qubits

Summary

Topological qubits offer a novel pathway to scalable quantum computing by simultaneously allowing for ease of coupling between qubits and strong decoupling of qubits from noise and dissipation. The most promising direction explores the topologically induced protection of theoretically predicted exotic quasiparticles, the so-called Majorana Zero Modes or MZMs. To-date MZMs, which follow non-Abelian statistics, have largely evaded unambiguous experimental demonstration. This project aims to provide a suitable material platform to realize MZMs. To achieve this, we develop a high-mobility semiconductor layer structure in order to observe the experimental signature of Majorana fermions on a platform that can be readily scaled and advanced to logical qubit devices. This project utilizes the molecular beam epitaxy (MBE) facility, the Quantum NanoFab and Characterization facility, and cryogenic measurement facilities available at UW to produce high-mobility material and turn epitaxial heterostructures into working devices. Furthermore, we collaborate with Jonathan Baugh’s group on quantum transport, fabrication and cryogenic measurements. This project advances all stages of developing a device based on topological qubits: design, MBE growth, fabrication and final testing. We would like to demonstrate and use the non-Abelian statistics of Majorana fermions to form topological qubits in epitaxial heterostructures and produce devices that could in the future lead to topologically protected quantum computers.

Figure 1. Concept visualization of two bound Majorana Zero Modes (MZM, in red), under a superconductor island (grey), all within a gate-defined quantum wire. The semi-transparent blue layer represents the host two-dimensional electron gas in the semiconductor single crystal.