Epitaxial Phase-Biased Josephson Junctions
Abstract
Much progress has been made on reducing qubit errors across hardware modalities in current qubits, through incremental optimization,and betting on elaborate error-correcting codes. A fundamentally different approach that could potentially revolutionize quantum com,puting is to use non-Abelian quasiparticles as a foundation of an intrinsically fault-tolerant system. The experimental study of to,pological phases of matter is a nascent, albeit growing, field, and to leverage them for useful applications will require significan,t advancements in our understanding of the fundamental physics of Majorana zero modes (MZMs).Numerous proposals to realize MZMs in d,ifferent condensed matter systems have been put forward. Some ideas progressed further than others. A useful way to asses any given,proposal is based on four criteria: (1) Is the proposal well grounded, i.e. do materials parameters favor Majorana or is it unlikely, to occur? (2) Is it verifiable, is there a measurement that can reveal thepresences of Majorana (3) Is it braidable, can non-Abelia,n statistics be demonstrated? And finally, (4) Is it scalable - can a useful quantum computing device be built in the future?The sup,erconductor-semiconductor platform check all four questions with a strong yes . Standard semiconductors are advantageous over other, materials systems in many ways. Most importantly, they are supported by decades of semiconductor research and are amenable to highl,y-refined molecular beam epitaxy growth and CMOS fabrication techniques. Integration of semiconductors with superconductors has also, advanced forward dramatically in the last decade thanks to growing interest in mesoscopic and topological superconductivity researc,h. However, Majorana research has been strongly focused on semiconductor nanowires which require large magnetic fields to enter the,topological Majorana phase, are difficult to scale, and pose geometric limitations for braiding.Our approach is based on two-dimens,ional (2D) superconductor-semiconductor heterostructures which have potential to resolve the challenges of the nanowire approach and, push this research field beyond the unambiguous demonstration of MZMs, to their manipulation and, ultimately, scaled devices. We sh,all use phase-controlled planar Josephson junctions (JJs) to generate, verify, and manipulate MZMs. The phase bias removes the need,for large magnetic fields, while two-dimensionality allows for flexible device designs. We shall work with high-mobility and strong,spin-orbit coupling (SOC) semiconductors, InAs, which already have a strong track record in Majorana research. On the superconductor, side, we shall go beyond the standard Al, which has a small gap, and develop new materials such as Ta, Sn and Nb with larger gaps t,o access larger phase space to explore topological effects, and ultimately stronger topological protection.This abstract is approved, for public release.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 07, 2022
- Source ID
- N000142212764
Entities
People
- Javad Shabani
Organizations
- New York University
- Office of Naval Research
- United States Navy