Work

X-ray diffraction from smectic multilayers: crossover from kinematical to dynamical regime

Year: 2025

Type: article

Abstract: We study X-ray diffraction in smectic liquid crystal multilayers. Such systems are fabricated as freely suspended films and have a unique layered structure. As such, they can be described as organic Bragg mirrors with sub-nanometre roughness. However, an interesting peculiarity arises in the diffraction from these structures: the characteristic shape of diffraction peaks associated with dynamical scattering effects is not observed. Instead, the diffraction can be well described kinematically, which is atypical for Bragg mirrors. In this article we investigate the transition between the kinematical and dynamical regimes of diffraction. For this purpose, we analyse the reflection of synchrotron radiation from a real liquid crystal sample with both kinematical and dynamical theories. On the basis of these theories, we derive a quantitative criterion for the transition from the kinematical to the dynamical regime. This, in turn, allows us to explain the peculiar diffraction behaviour in smectic films with thicknesses exceeding thousands of molecular layers.

Source: Journal of Applied Crystallography

DOI: 10.1107/s1600576725008076

Authors: Vladimir V. Samsonov, Konstantin V. Nikolaev, Boris I. Ostrovskii, Sergey N. Yakunin

Institutions: Lomonosov Moscow State University, Kurchatov Institute, Moscow Institute of Physics and Technology, Osipyan Institute of Solid State Physics RAS

Language: English

Topic: Liquid Crystal Research Advancements

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: Ministry of Education and Science of the Russian Federation, Russian Science Foundation

Awards: G2529347216, G3147322738