Fysikum team unveils promising avenue towards the realization of elusive parafermions
In their latest publication in Nature Communications, researchers Hui Liu, Raul Perea-Causin, and Emil J. Bergholtz demonstrate that Fibonacci parafermions—exotic quasi-particles which have so far evaded experimental realization—can emerge in experimentally accessible moiré structures formed by overlaying two-dimensional materials with a twist.
Artistic illustration of parafermions in a twisted multilayer graphene structure. Credit: Giuseppe Meneghini.
The trio, based in the Department of Physics at Stockholm University, has shown that the so-called Z3 Read-Rezayi phase is stable in a theoretical model of twisted multilayer graphene. The findings imply the emergence of Fibonacci parafermions, exotic quasi-particles that were proposed to appear in quantum Hall systems but have not been realized so far due to their low stability or owing to the challenging nature of the proposed setups. The Stockholm-based work puts forward moiré structures as a promising platform to finally realize parafermions. In contrast to previous setups, moiré materials offer an experimentally accessible and widely tunable playground where parafermions could be stabilized even in the absence of a magnetic field.
Parafermions are distinguished from normal fermions (such as the electrons, protons, and neutrons that make up the matter around us) through their so-called non-Abelian exchange statistics. This process, which essentially consists in swapping two or more particles in a manner reminiscent of braiding, has, in principle, the potential to be exploited for novel technologies such as fault-tolerant universal quantum computation. In this sense, Fibonacci parafermions are superior to Majorana zero-modes—simpler quasi-particles whose realization remains controversial and which, by themselves, fall short of allowing for universal computation. The present work suggests that Fibonacci parafermions might even be more stable than their Majorana counterparts in moiré materials due to the absence of competing phases. Overall, the findings indicate that moiré materials, which are becoming a popular platform for the exploration of exotic quantum phases, hold the key for the first ever experimental realization of parafermions.
The full study has been published in Nature Communications:
H. Liu, R. Perea-Causin, E. J. Bergholtz. Parafermions in moiré minibands. Nature Communications16, 1770 (2025). https://doi.org/10.1038/s41467-025-57035-x"
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Last updated: 2025-02-24
Source: Gunilla Häggström, Communications Officer, Fysikum