Thermodynamic Imaging Reveals the Nature of Out-of-Equilibrium Transport in Moiré Graphene - Part II

Recent experiments on nonlinear transport in graphene/hBN moiré system have observed striking transport characteristics. At high bias, sharp gate-tunable differential resistance peaks were observed. Similar phenomenology has been seen in twisted bilayer graphene near and at the magic angle. These tunable resistance peaks were associated with the Schwinger mechanism of electron-hole pair creation. However, to date, these observations are based only on transport measurements, which probe only integrated behavior, and cannot reveal the microscopic structure along the bulk of the sample.

In Part II of this talk, we will present a new technique that combines a scanning nanotube single electron transistor (SET) with conventional electrical measurements, to image thermodynamic properties of out-of-equilibrium flows. These measurements reveal an unusual thermodynamic signature that appears concomitantly with the resistive peaks, marking the transition between low and high resistivity states, shedding new light on the true origin of the phenomenon.