Extended Data Fig. 7: Long-lived dynamics of the atomic defect.

a, Oscillations of the lightwave-driven tunnelling current induced by THz excitation can be seen up to 100 ps after excitation on an orbital lobe of the vacancy in monolayer WSe₂/Au(111). Pump and probe peak fields, 0.32 E₀. b, LW-STS for delay times τ = 88.5 ps (red) and 90 ps (yellow) exhibit the same phase dependence as for τ = 8.8 ps and 10.2 ps (Fig. 3c): at a minimum of the current oscillations (yellow circle in a), the tunnelling onset into D₁ is shifted to higher energies. Pump peak field, 0.46 E₀. c, Fourier transforms of pump-probe traces of the lightwave-driven current for 7 ps < τ < 95 ps (grey) and corresponding delay-time interval of the near-field waveform of the pump pulse containing its time-delayed replicas (Methods) (pink). The latter result in a multi-peak spectrum present in both traces featuring an envelope similar to the pump pulse itself (dashed). A pump-probe current trace reveals the strongly enhanced peak at 0.34 THz (orange shaded area), which we can attribute to the drum mode frequency. The Fourier amplitudes are normalised to their values at 0.25 THz. Data in a: mean values ± standard deviations of bootstrapped datasets (Methods); 12 measurements per data point, each measurement: 18.3 million laser pulses. b: mean value ± standard deviation of 2 datasets, each measurement: 219.6 million laser pulses.