Fig. 2: Rate and time dependent hysteresis loops and gate tuning of the quality factors Q.
From: High-quality-factor viscoelastic nanomechanical resonators from moiré superlattices
a Resonant frequency loops at different step rates, dVdc/dt. ○, □, ♢ correspond to a slow, medium, and fast step rate, respectively. The arrows indicate the direction of the sweep. b Schematic of the flexural drum vibration (top panel) and the reduced viscoelastic model (bottom panel). The membrane flexural motion is modelled by a mass (M) connected to a spring (k) and a dashpot (ηs) in parallel (Kelvin-Voigt model) to include the effects of viscoelasticity. D is the diameter of the drum. c Experimental and fitted (ϵ0 = 2.67 × 10−4 and ηs = 10.5 × 1015 Pa s) resonant frequency loop under the slow stepping rate (○). d Experimental and calculated ΔVdc as a function of dVdc/dt. e Evolution of fr and Q upon repeating the forward-then-backward step sweep of Vdc in three consecutive rounds (1st, 2nd, 3rd) for two traces (trace 1 and trace 2) corresponding to different initialisations. ts is the time interval (only denoted between two different rounds) when the step direction is reversed.
