  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.
