Extended Data Fig. 7: Quantum mechanical wave-packet motion in the TSS.
From: Tunable non-integer high-harmonic generation in a topological insulator
a, Top: normalized vector potential, ATHz, of the driving multi-THz waveform (frequency νTHz = 25 THz; peak electric field ETHz = 1 MV cm−1). Dashed lines highlight the zero crossings of the vector potential and the momentum space trajectories. Bottom: group velocity components of the electrons in the TSS parallel (vx, blue) and perpendicular (vy, red) to the THz driving field calculated by solving the full time-dependent Schrödinger equation. Both components reverse sign during zero crossings of the momentum space trajectories. b, Real space trajectory of lightwave-driven Dirac electrons calculated by the velocities in a.
