Researchers have generated high-quality atom diffraction data from graphene, which could lead to new ways to measure surface interactions.

A beam of neutral atoms striking a material can produce a diffraction pattern that is sensitive to short-range interactions between the atoms and the surface. Building on recent developments, Pierre Guichard from the University of Strasbourg in France and collaborators have now used a fast hydrogen beam to probe single-layer graphene, producing the sharpest graphene diffraction patterns to date [1].

Early atom diffraction experiments predominantly looked at reflection, because atoms transmitted through a material tend to lose their wave-like coherence. Recently, however, transmitted atoms were shown to produce a diffraction pattern from single-layer graphene [2]. The trick was to use fast atoms that traverse the target quickly, minimizing coherence-destroying interactions.

Properties that remain unchanged when materials are stretched or bent, which are broadly referred to as topological properties, can contribute to the emergence of unusual physical effects in specific systems.

Over the past few years, many physicists have been investigating the physical effects emerging from the topology of non-Hermitian systems, open systems that exchange energy with their surroundings.

Researchers at Nanyang Technological University and the Australian National University set out to probe non-Hermitian topological phenomena in systems comprised of light and matter particles that strongly interact with each other.