Cotunneling, current blockade, and backaction forces in nanobeams close to the Euler buckling instability

Single-electron transistors embedded in a vibrating nanoresonator such as a doubly-clamped carbon nanotube exhibit effects stemming from the coupling between electronic and vibrational degrees of freedom. In particular, a capacitive electromechanical coupling induces a blockade of the current at low bias voltage. It has been recently shown theoretically within a sequential-tunneling approximation that this current blockade can be enhanced by orders of magnitude when the suspended structure is brought to the Euler buckling instability. Here, we investigate the role of cotunneling on the predicted enhancement and show that the latter is not suppressed by cotunneling effects. We further demonstrate that despite the fact that the current blockade is difficult to measure far from the Euler instability, the backaction of the current flow on the nanobeam frequency may be easier to observe.