Majorana Fermions in Superconductor-Semiconductor Nanowire Systems
Abstract
Objective:Since the initial prediction by Italian physicist Ettore Majorana more than 70 years ago, the search for the odd particle now bears his name -- Majorana fermion (MF), which is also its own anti-particle, has shifted from high energy physics to relatively standard condensed matter systems. Indeed initial experimental results with excitations that are consistent with MF has been observed and reported by several research groups worldwide. If confirmed, MF has far reaching implications in robust quantum information processing and possibly other areas of applications. The objectve of this Basic Research Challenge (BRC) project is to carry out fundamental research to achieve a thorough understanding of the mechanisms, conditions and materials constraints that ultimately leads to unambiguous demonstration of Majorana fermions in solid state systems.Approach:The team will pursue the mainstream line of investigation of Majorana fermions in devices based on semiconductor nanowires. Not only has this materials system been used to perform many of the initial Majorana experiments, it also has a large untapped potential to take the field forward. One big advantage is in the nanowire device architecture that allows placing contacts on top, underneath and next to the nanowire. This makes it easy (lego-like) to assemble multi-terminal devices for probing unobserved properties of Majorana fermions, and integrating extra control knobs for additional functionality and self-checks. The second important advantage is the high quality of nanowire crystals andthe large variety of their morphology and composition ? a toolkit that enables a high degree of semiconductor tailoring for experimental demands. In this program, improved nanowire materials will fuel the new generation of experiments such as advanced microwave measurements to achieve the next level of understanding of hybrid systems and of Majorana fermions.ONR Mission/Relevance:Scientifically, this project is aimed at developing the basic physics of the Majorana fermion and its dynamics in the context of new topological materials and heterostructures. Practically, the project will lay the foundation for future electronic devices with possible order-of-magnitude reductions in computational energy that enable advanced computing schemes that will contribute directly to the Naval goal of information dominance. There have been no prior efforts in this topic at ONR. As a relatively unexplored area, there is an intrinsic opportunity to attract new performers into the field and to engage with the Navy.SOW:This program will address all the key questions related to Majorana fermions in semiconductor nanowires, short of demonstrating their non-Abelian exchange. It will be based on the world?s highest quality semiconductor nanowires. The experimental component of the project will be based on the synergy of quantum transport and microwave techniques, through this combination opening a new dimension to the Majorana field. Theoretical components will be integrated with all experiments to both guide and analyze the experimental development. On the materials science side, the team will improve nanowire materials in order to reach increased mobility, and to achieve the truly one-dimensional regime. On the transport experimental side, the team will study the phase transition into the topological superconducting state through tunneling experiments. Observation and mapping out of the topological phase transition is a key missing signature of Majorana fermions. The team will also study non-local properties of Majorana fermions in multi-terminal devices. This effort addresses the predicted notion that Majoranas always arise in pairs. The interplay of Andreev bound states and topological superconductivity will be studied in superconducting interference experiments. This work not only addresses one of the most potent alternative scenarios for zero-bias peaks, but also studies the predicted exotic decoupled b
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 21, 2018
- Source ID
- N000141612270
Entities
People
- Sergey M Frolov
Organizations
- Office of Naval Research
- United States Navy
- University of Pittsburgh