Experimental setup and nanowire resonators. (a) Scheme of the in situ TEM fiber-assembled electromechanical holder. (b)–(d) A selected stationary nanowire, its first harmonic resonance mode, and second harmonic resonance mode, respectively. Scale bar: 2 μ m . (e) and (f) A vibrating nanowire with moderately small resonance amplitude, and its resonance peak fitted by Lorentzian line. Scale bar: 2 μ m .