@article{67146,
  abstract     = {{<jats:p>
                    High-harmonic generation in solids enables probing of strong-field electron dynamics in condensed matter and the development of compact ultrafast light sources. Whereas most studies have focused on above-bandgap high-order harmonics, which are usually interpreted through short electron-hole trajectories that recombine within one optical cycle, the microscopic origin of low-order emission near the bandgap remains poorly understood. Here, we investigate near-bandgap harmonic generation in ZnO by combining semiconductor Bloch equations with a complex-time quantum-trajectory analysis. Our results indicate that these harmonics are not a continuation of the short trajectory. Rather, they originate from multiple-scattering trajectories, in which the electron-hole pair undergoes repeated Bragg scattering at the Brillouin-zone boundary and electron-hole reencounter near the
                    <a:math xmlns:a="http://www.w3.org/1998/Math/MathML">
                      <a:mi mathvariant="normal">Γ</a:mi>
                    </a:math>
                    point before the actual recombination occurs. We identify that the imaginary part of the electron-hole displacement provides a practical diagnostic of the residual tunneling memory. Real-space electron-hole overlap alone does not imply coherent recombination unless the full complex displacement vanishes. These results clarify the microscopic picture of near-bandgap harmonic emission in ZnO and offer a framework for interpreting phase-resolved strong-field dynamics in solids.
                  </jats:p>}},
  author       = {{Huo, Xunqin and Liu, Xiwang and Yang, Shidong and Song, Xiaohong and Meier, Torsten and Yang, Weifeng}},
  issn         = {{2643-1564}},
  journal      = {{Physical Review Research}},
  number       = {{3}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Near-bandgap harmonic generation in solids from multiple scattering revealed by complex quantum trajectories}}},
  doi          = {{10.1103/l939-jglf}},
  volume       = {{8}},
  year         = {{2026}},
}