Charge detection using nano-resonators

The separation of leaves in gold leaf electroscopes indicates the amount of charge on them. Detectors that can accurately measure small fluctuations in charges are extremely important in a lot of applications including quantum sensingMost of these sensitive detectors such as the ones based on Josephson junctions and single-electron transistors operate at temperatures below 1 K. These detectors rely on rapid change in the output in response to minute charge fluctuations at the input. Nonlinear systems at bifurcation points do exhibit such abrupt changes in output for small changes in the input. Such bifurcation amplifiers have previously been demonstrated using Josephson junction and mechanical resonators. Previous demonstrations using mechanical resonators were able detect charge fluctuations on the order of 100 electrons at room temperature. In our work, we have taken advantage of the exquisite force sensitivity of 2D material nano-electromechanical resonators in conjunction with a bifurcation amplifier implementation to sense charges on the order of 10 electrons in real-time at room temperature. We have also implemented a set-reset flip-flop using the same device to record short-lived charge fluctuations until an erase/reset operation is performed.  



The paper is published in APL.

More details can be found here

Congratulations Aneesh, Nishta and Swapnil!

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