Excitonic Chern insulator in a moiré lattice (Part1)

Characterization of thermodynamics properties is of great importance in the study of strongly correlated two-dimensional systems. While existing techniques rely on electrical measurement of thermodynamics, optical detection of thermodynamic quantities has not yet been reported. Compared to electrical measurement, optical measurement provides spatial resolution, time resolution and energy resolution. Here we report the first realization of optical characterization of thermodynamics properties by inserting an TMD exciton sensor close to the sample. The band edge of the exciton sensor is accurately determined by optical reflection spectroscopy on sensor 1s exciton resonance and actively adjusted through a feedback mechanism to the fermi level, providing a reference point for chemical potential readout in the sample. Furthermore, we extract other thermodynamics variables including charge compressibility, polarization, and magnetization from measured chemical potential of the sample through Maxwell’s relation. This technique provides a powerful platform for local thermodynamics measurement and has great potential in realizing spatially resolved transport measurement and time-resolved characterization of thermodynamics.