The Joint Condensed Matter Seminar (JCMS) series is organised by KTH Royal Insitute of Technology, Nordita, and Stockholm University.
On Monday, February 10th, 2025 from 11 am to 12 am we will host a seminar by Raul Perea Causin from Stockholm University.
Parafermions and Hall crystals in moiré superlattices
Moiré superlattices, formed by stacking twisted 2D materials, have emerged as a highly tunable platform for exploring strongly correlated phases. In particular, the realization of fractional Chern insulators (FCIs), which exhibit a fractionally quantized Hall conductance at zero magnetic field, has spurred the search for exotic phases that are either elusive or absent in traditional quantum Hall systems. Performing exact diagonalization on an exemplary moiré band, we demonstrate the stability of moiré-based Fibonacci parafermions—which could serve as building blocks for fault-tolerant universal quantum computing. Additionally, we predict that a 2/3-filled moiré band with Chern number C=2 hosts a robust Hall crystal—a many-body phase exhibiting both crystalline order and integer-quantized Hall resistance. Our results establish moiré Chern bands as promising candidates for realizing parafermions and uncover the robustness of Hall crystals arising from bands with higher Chern number, all in the absence of a magnetic field.