Diffraction of atomic matter waves through a 2D crystal

TL;DR

This paper demonstrates the first coherent diffraction of helium and hydrogen atoms through a 2D graphene crystal at high energies, revealing new possibilities for atomic surface analysis.

Contribution

It introduces a novel method for atomic diffraction through materials, overcoming previous limitations to subatomic particles and enabling detailed surface studies.

Findings

Coherent scattering observed for helium and hydrogen atoms.

Diffraction occurs despite high kinetic energies and electronic interactions.

Limited momentum transfer preserves coherence during diffraction.

Abstract

Diffraction of atoms from surfaces provides detailed insights into structures, interactions, and dynamical processes. However, currently the method is limited to measurements in reflection - diffraction through materials has only been demonstrated for subatomic particles and is an outstanding challenge for atoms. We diffract helium and hydrogen atoms at kiloelectronvolt energies through single-layer graphene at normal incidence. Despite the atoms' high kinetic energy as well as coupling to the electronic system of graphene, we observe coherent scattering. This preservation of coherence was the result of the limited momentum transfer between the projectile and the lattice, resulting from interaction times on the femtosecond scale.