Sensing and remembering few-electron charges using an MoS₂ nanoresonator

Bifurcation amplifiers are useful in quantum sensing to detect weak signals with high sensitivity. These devices have been previously realized using Josephson junctions. However, their operation is restricted to cryogenic temperatures. Nanomechanical bifurcation amplifiers offer the advantages of room-temperature operation with ultra-high sensitivity to external stimuli. We experimentally demonstrate a nano-electromechanical bifurcation amplifier made of MoS₂, that can detect charge fluctuations less than 10 electrons in real-time at room temperature, in open-loop measurements. The detection is based on switching between two states in the parametrically-excited nonlinear resonator. Furthermore, the same device can also function as a set-reset latch memory for short-lived charge perturbations. The minimum detected charge is an order of magnitude improvement from mechanical electrometers made of bulk materials. These devices hold significant promise for quantum sensing and nanomechanical sensing.