Resistively-detected electron spin resonance study on Bernal bilayer graphene

Spin is one of the important quantum states in graphene, but it is challenging to directly detect with traditional methods (such as ESR) due to a low spin count. However, resistively detected electron spin resonance (RDESR) has been demonstrated to provide vital information about electronic order and spin properties in strongly correlated systems and, recently, a study on magic-angle twisted bilayer graphene has observed microwave induced collective excitations originated from Dirac revivals of flat band [1]. In this talk, we will present our RDESR study on ¹²C and ¹³C enriched Bernal bilayer graphene devices. We detect strong RDESR signal in the small carrier density and large displacement field regions, and no RDESR signal elsewhere. No obvious change of the resonance positions has been observed across different isospin polarized regions, but we do find differences of the resonance spectrum compared to magic-angle twisted bilayer graphene which may have implications on the intervalley exchange interactions and the nature of electronic transport in the system.

[1] Morissette, Erin, et al. "Dirac revivals drive a resonance response in twisted bilayer graphene." Nature Physics (2023): 1-7.