講演情報
[9p-S5-6]Shape and Edge Dependence of High-Harmonic Generation in Graphene Nanoflakes
〇(PC)Arqum Hashmi1, Siyuan Li1, Kazuhiro Yabana2, Kenichi L. Ishikawa1 (1.Tokyo Univ., 2.Univ. of Tsukuba)
キーワード：
Graphene nanoflakes、TDDFT、HHG
We investigate hexagonal, rectangular, and triangular hydrogen-terminated Graphene nanoflakes (GNFs) of size <1.5nm driven by a linearly polarized laser pulse. The calculated HHG spectrum exhibits a pronounced dependence on both flake geometry and the polarization direction relative to the armchair and zigzag edges. We find that laser-induced charge polarization generates a screening field that significantly modifies the local electric field experienced by electrons. Consequently, the harmonic yield and spectral cutoff differ substantially from those predicted within the independent-particle approximation, demonstrating the important role of dynamical screening in finite GNF. Interestingly, the HHG cutoff extends beyond that predicted by the conventional three-step model, irrespective of the flake geometry. This behavior suggests the presence of finite-size effects that modify the electron dynamics and contribute to the extended energy cutoff in GNFs.