Hadrien Vignaud : Deep-UV bleaching of charge disorder in encapsulated graphene: Revealing even denominator fractional quantum hall states. 

Since its discovery in 1982, the fractional quantum Hall effect (FQHE) has continuously fascinated condensed-matter physicists, partly due to the emergence of exotic quasiparticles carrying fractional charge and, in some cases, potentially obeying exchange statistics far richer than the usual fermion-boson dichotomy. Central to these discoveries has been a decades-long effort to produce cleaner two-dimensional electron systems, allowing ever more fragile interaction-driven states to emerge. Since its isolation in 2004, similar efforts have been pursued in graphene. Over little more than a decade, advances in device fabrication have transformed graphene-based systems into exceptionally clean platforms, providing access to an ever-expanding landscape of correlated states. Despite these advances, further reductions in disorder have become increasingly difficult in recent years. In this talk, I will present our recent work showing that a brief UV illumination provides a simple route to overcome this limitation [1]. Remarkably, devices initially considered too disordered can recover and reveal fragile electronic states that were previously hidden by disorder. This approach also allowed us to observe numerous even-denominator fractional quantum Hall states in graphene, including potential candidates for non-Abelian phases.