ENHANCING TOPOLOGY WITH TWISTRONICS
Abstract
A recent breakthrough in condensed matter physics is the discovery of superconductivity and other intriguing correlated phases in two atomically thin layers of carbon, layered with a small relative twist angle. This discovery is exciting for its novelty, as such phases are never observed a single layer of graphene, as well as for its simplicity. It is also important, as it presents a tunable recipe to achieve novel phases of matter. The discovery of twisted bilayer graphene has launched the field of “twistronics.” The proposed the-oretical work will apply the twistronic technology to another phase of matter: topological insulators and semimetals. Topological phases have the unusual property that they can be insulating inside and conducting on their surfaces. When topological phases become superconducting, they exhibit Majorana fermions, un-usual particles that are their own antiparticle, which can form the basis of a topological quantum computer. In the proposed theoretical work, we will develop a framework to apply twistronics to topological ma-terials. The goal is to realize a topological superconductor or other correlated topological phase, tunable via twist angle or pressure. The proposed work has three main objectives: 1) to derive an effective theory of a moir´e superlattice on the surface of a 3D topological insulator; compute superconducting instabilities; and optimize the material combinations; 2) to derive a low-energy theory for a twisted Dirac heterostructure on any 2D Bravais lattice and determine how the interacting instabilities depend on the unit cell and symmetry; and 3) to derive the low-energy theory for a twisted nodal line semimetal and determine whether it leads to flat bands whose leading pairing instability is a topological crystalline superconductor. The work will be accomplished through analytical and numerical calculations. The end result will be new and achievable recipes for topological correlated phases.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2021
- Source ID
- FA95502010260
Entities
People
- Jennifer Cano
Organizations
- Air Force Office of Scientific Research
- Research Foundation for the State University of New York
- United States Air Force