Thermal effects on helium scattering from LiF(001) at grazing incidence

TL;DR

This study uses a semiquantum theoretical approach to analyze how thermal vibrations influence helium atom diffraction patterns from LiF(001) surfaces at various temperatures, providing insights for surface analysis techniques.

Contribution

It introduces the P0-SIVR method to model thermal effects on GIFAD patterns, advancing understanding of temperature influence on surface diffraction.

Findings

Thermal fluctuations significantly alter diffraction pattern intensities.

Azimuthal and polar spectra are strongly affected by temperature.

Results align with experimental data at room temperature.

Abstract

Grazing-incidence fast atom diffraction (GIFAD) is an exceptionally sensitive method for surface analysis, which can be applied not only at room temperature but also at higher temperatures. In this work we use the He-LiF(001) system as benchmark to study the influence of temperature on GIFAD patterns from insulator surfaces. Our theoretical description is based on the Phonon-Surface Initial Value Representation (P0-SIVR) approximation, which is a semiquantum approach that includes the phonon contribution to the elastic scattering. Within the P0-SIVR approach the main features introduced by thermal lattice vibrations on the angular distributions of scattered projectiles are investigated as a function of the crystal temperature. We found that azimuthal and polar spectra are strongly affected by thermal fluctuations, which modify the relative intensities and the polar spread of the interference structures. These findings are relevant for the use of GIFAD in surface research. Moreover, the present results are contrasted with available experimental data at room temperature.