Towards RF local electronic compressibility measurements with in situ displacement field control using a scanning multiprobe microscope

Single electron transistors (SET) are powerful electrometers that can extract thermodynamic quantities such as electronic compressibility, chemical potential, entropy, etc. Conventionally, a scanning SET is hosted on the apex of a quartz pipette. This enables small sensor sizes and tip-sample distances, facilitating high spatial resolution and signal to noise ratios. However, expanding SET measurement capabilities is difficult in this paradigm. In this talk, we present efforts to increase the accessible experimental phase space of SETs in our scanning multiprobe architecture. Since multiprobe sensor development is compatible with conventional nanofabrication processes, one can introduce nearby circuit elements to modify the sensor and sample environments. We leverage this to fabricate sensors for measuring local electronic compressibility with in situ displacement field control and at RF frequencies. We benchmark their performance and show preliminary efforts to measure local electronic compressibility of a van der Waals heterostructure.