We demonstrate experimentally that composite fermions in monolayer graphene display weak antilocalization. Our experiments deal with fractional quantum Hall (FQH) states in high-mobility, suspended graphene Corbino disks in the vicinity of $\nu =1/2$. We find a strong temperature dependence of conductivity $\sigma$ away from half filling, which is consistent with the expected electron-electron interaction-induced gaps in the FQH state. At half filling, however, the temperature dependence of conductivity $\sigma \left(T\right)$ becomes quite weak, as anticipated for a Fermi sea of composite fermions, and we find a logarithmic dependence of $\sigma$ on $T$. The sign of this quantum correction coincides with the weak antilocalization of graphene composite fermions, indigenous to chiral Dirac particles.

• Received 18 December 2016

DOI:https://doi.org/10.1103/PhysRevB.97.075113