CAREER: Realization, Manipulation, and Interaction of Majorana Kramers Pairs

University Of Texas At Dallas, Richardson TX

Investigators

Abstract

NONTECHNICAL SUMMARY This CAREER award supports theoretical research and education in the rapidly developing area of topological states of electronic matter. Over the past decade, the discovery of topological insulators has revolutionized our understanding of the quantum world. The bulk of a topological insulator is insulating, but the surfaces and edges are metallic. A topological insulator is robust; it persists even under deformations of the material. In mathematics, topology is concerned with the properties of an object that are preserved under continuous deformations. Superconductors embody one of the most well studied macroscopic quantum phenomenon. Below a characteristic critical temperature, the electrical resistance of a superconductor drops to zero and magnetic fields are expelled from their interior. Like their topological insulator cousins, topological superconductors exhibit surface states; however, these are predicted to have curious Majorana Fermions, electrons that are correlated in such a way that they behave like a particle that has unusual properties; as a consequence, they may be useful as building blocks for computing and memory in a quantum computer. First proposed as an elementary particle, Majorana Fermions are also fundamentally interesting; a Majorana Fermion is its own antiparticle. The discovery of superconductors that exhibit topological properties has proved difficult. To this end, the PI will leverage well-understood topological and superconducting materials to design new materials systems for realizing topological superconductivity. The PI plans to investigate new phenomena that can arise involving Majorana Fermions and their interplay with crystal symmetry, topology, and interactions in topological superconductors. This research is aimed to stimulate the realization of new phases of electronic matter that can appear in materials. The PI aims to investigate new avenues for realizing topological quantum computing and Majorana Fermion based electronics. The research will stimulate and connect with experiments. The education component involves the implementation of a multi-layered outreach plan that includes: 1) mentoring and training graduate, undergraduate, and high-school students participating in this research, 2) developing an unconventional dual-level course on topological quantum matter, and 3) creating animated online video lessons for global physics education of the general public. In these activities, the PI is committed to promote increasing participation in science. This CAREER award will contribute to the preparation of future scientists and engineers to discover, invent, and innovate. TECHNICAL SUMMARY This CAREER award supports fundamental research into the realization of symmetry protected topological superconductivity and manipulation of Majorana Kramers pairs in order to develop a deeper understanding of the interplay between symmetry, topology, and interaction. The past decade was an exciting era for condensed matter physics. The discovery of topological insulators has led to an ongoing revolution deepening understanding of quantum matter. The critical temperature of iron-based superconductors has been made unexpectedly high in atomically thin layers. The delicate two-channel Kondo effect as a non-Fermi-liquid paradigm has been achieved in sophisticatedly designed devices. These seemingly unrelated advances in distinct areas can be deeply correlated in a time-reversal-invariant topological superconductor hosting Majorana Kramers pairs. The central goals of this project are: 1) to realize such topological superconductors by designing new material systems involving iron-based superconductors, and 2) to investigate the consequences of Majorana Kramers pairs by studying Josephson effects and many-body interactions mediated by them. The research will be carried out using a diverse set of techniques: phenomenological modeling, topological band theory, first-principles calculations, many-body simulations, and symmetry analysis. The PI aims to establish materials platforms for realizing time-reversal-invariant topological superconductors and manipulating Majorana Kramers pairs. In particular, he aims to identify iron-based topological superconductors with high critical temperatures and advance ideas for the braiding and interaction of Majorana Kramers pairs. Directly applicable to ongoing experiments, these results could advance current knowledge of topological phases of matter and their interplay with symmetry and interaction. Alongside the research, the PI will implement a multi-layered outreach plan that involves: 1) mentoring and training graduate, undergraduate, and high-school students participating in the research, 2) developing an unconventional dual-level course on topological quantum matter, and 3) creating animated online video lessons for global physics education of the general public. In these activities, the PI is committed to promote increasing participation in science. This CAREER award will contribute to the preparation of future scientists and engineers to discover, invent, and innovate. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.