Thermal probe of correlated states in bilayer graphene

Measurement of thermodynamic properties at half-filled Landau levels (LLs) such as thermoelectric power (TEP) can offer a view which is distinct from that offered by other techniques. For example, in the case of a clean non-interacting 2D electron system, it has been shown that TEP is proportional to the transport entropy of the 2D electron system. A similar connection between TEP and entropy was later proved to hold for strongly interacting electrons in high magnetic fields. This makes TEP a powerful tool to reveal statistical properties of FQH states as the entropy carried by non-Abelian quasiparticles is predicted to be anomalously large. In this talk, I will present magneto-TEP studies of high-quality Bernal stacked bilayer graphene devices which exhibit well-developed FQH states at relatively low magnetic fields. Our data indicates that TEP can be a more sensitive probe of FQH states compared to resistivity measurements. The observed FQH states are being studied further by temperature and magnetic field dependence TEP measurements to probe their topological properties.