Neighboring Atom Collisions in Solid-State High Harmonic Generation

Ruixin Zuo,Weifeng Yang,Shidong Yang,Huynh Thanh Duc,Xiaohong Song,Wolf-Rüdiger Hannes,Marcelo Ciappina,Alexander Trautmann,Torsten Meier,Guifang Wang

doi:10.34133/2021/9861923

Abstract

High harmonic generation (HHG) from solids shows great application prospects in compact short-wavelength light sources and as a tool for imaging the dynamics in crystals with subnanometer spatial and attosecond temporal resolution. However, the underlying collision dynamics behind solid HHG is still intensively debated and no direct mapping relationship between the collision dynamics with band structure has been built. Here, we show that the electron and its associated hole can be elastically scattered by neighboring atoms when their wavelength approaches the atomic size. We reveal that the elastic scattering of electron/hole from neighboring atoms can dramatically influence the electron recombination with its left-behind hole, which turns out to be the fundamental reason for the anisotropic interband HHG observed recently in bulk crystals. Our findings link the electron/hole backward scattering with Van Hove singularities and forward scattering with critical lines in the band structure and thus build a clear mapping between the band structure and the harmonic spectrum. Our work provides a unifying picture for several seemingly unrelated experimental observations and theoretical predictions, including the anisotropic harmonic emission in MgO, the atomic-like recollision mechanism of solid HHG, and the delocalization of HHG in ZnO. This strongly improved understanding will pave the way for controlling the solid-state HHG and visualizing the structure-dependent electron dynamics in solids.

Highlights

Collision dynamics lies at the heart of particle physics and constitutes one of the fundamental blocks in strongfield physics and attosecond science [1,2,3,4,5]
We identify a close correspondence between the Van Hove singularity points in the band structures and the backward scattering of electron/hole from neighboring atoms and map these effects onto the harmonic spectrum
To unveil the collision dynamics of electron/hole with other atoms in solids, we focus on the recently observed anisotropic High harmonic generation (HHG) in MgO reported in Reference [21]

Summary

Introduction

Collision dynamics lies at the heart of particle physics and constitutes one of the fundamental blocks in strongfield physics and attosecond science [1,2,3,4,5]. When the electric field reverses its direction, the electron could be driven back to collide with the atomic core. If the electron recombines with the parent ion, high-order harmonics (HHG) and attosecond photon bursts would be emitted; otherwise, the electron would be scattered away and high-energy electrons would be detected. The emitted high-energy photons and electrons encode structural and dynamical information about the atom or molecule they have left behind. The Ultrafast Science electron recollision with the ion/molecular core provides an efficient way to generate attosecond optical and electron pulses and an optical technique to probe the structure and ultrafast electronic dynamics in its natural time scale [6,7,8,9,10,11]

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