Extended Data Fig. 2: Subthreshold firing and memory effect in V₂O₃.

a, Applied voltage as a function of time. The pump–probe procedure consists of a super-threshold pulse first applied to trigger the IMT, followed, after a delay time τ, by a subthreshold probe pulse. The dashed line shows V_Threshold. b, Current versus time at T = 130 K when the voltage shown in a is applied with a delay τ = 100 μs between the pulses. The transition is triggered in both cases. c, Probability that the probe pulse will trigger the IMT (P_Trigger) as a function of τ, at T = 130 K. This probability was obtained by observing how many times the IMT was triggered in 100 pulses. The error bars were calculated using the standard deviation of the binomial distribution. P_Trigger is plotted for different V_Probe amplitudes: 0.5V_Th, 0.6V_Th, 0.7V_Th and 0.8V_Th (see key; V_Th = V_Threshold). Solid lines are fits to curves of the type αt^−β + γ, where α, β and γ are fitting parameters obtained by the least-squares method. d, Delay time τ_50%, at which the firing probability is 50%, plotted against T for a pulse with amplitude 0.6 V_Threshold. τ_50% was calculated using the fitting curves shown in c. Error bars were derived by uncertainty propagation, using the standard error of the fit.