Correlated Topological States in Moire Superlattices of Intrinsic Magnetic Topological Insulator
Abstract
This proposal aims to realize novel correlated topological magnetic states in moire superlattices of the intrinsic magnetic topological insulators (TI) MnBi2Te4 and MnBi4Te7 (collectively abbreviated as MBT), using magneto-optics, micro-scale ARPES and ultra-low temperature transport. The intersection between topology, magnetism, and correlation constitutes one of the most exciting scientific frontiers with profound implications both for advancing fundamental science and for enabling future technologies. Major challenges in quantum technologies and microelectronics can be overcome by delivering dissipationless electron transport, topological spin texture, long-range quantum entanglement and nonabelian anyon excitations, all of which can emerge from the interplay between topology, magnetism and correlations. Despite the exciting prospect, experimental progress has been critically hindered by the stringent requirements on material properties and tunability. For instance, flat bands with a nontrivial Chern number (i.e., flat Chern bands) have been proposed as a highly promising platform for correlated topological physics. In lab, we have both materials with flat bands (e.g. heavy fermion systems) and materials with nonzero Chern number (e.g. magnetically-doped TI films), but materials where the two intersect are exceedingly rare. To induce the correlated topological phenomena, we need to further place the chemical potential at fractional filling of the flat band, making the task even more challenging.We propose to tackle this exciting challenge by taking advantage of two recent developments. The first development is the recent synthesis of MBT, which realized the first intrinsic magnetic TI in a vdW structure. By exfoliating down to the ultra-thin limit, transport experiments have clearly demonstrated the robust Chern insulator state in the ferromagnetic (FM) phase. The second development is the recent seminal works on graphene and TMD moire superlattices. These studies uncovered many novel quantum phenomena. Moreover, they demonstrated moir´e pattern’s remarkable abilities to modify a vdW material’s symmetry and electronic properties away from the natural form. In particular, the moire pattern can (1) engineer spatial symmetries, (2) generate superlattice with spatially-varying atomic registry, and (3) induce flat bands and correlation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 22, 2024
- Source ID
- FA95502310040
Entities
People
- Suyang Xu
Organizations
- Air Force Office of Scientific Research
- President and Fellows of Harvard College
- United States Air Force