Future applications of the high-flux thermal neutron spectroscopy: the ever-green case of collective excitations in liquid metals

ABSTRACT The European landscape of neutron sources for research applications is changing and the major European joint effort, the European Spallation Source (ESS) currently under construction in Lund (Sweden), is progressing. The high flux source ESS is designed to deliver slow neutrons with a long-pulse time structure, a rather unique feature, with characteristics optimised to maximise the instrument performances and the experimental throughput. This is expected to result in unprecedented scientific capability over broad research areas. Major breakthroughs are likely to take place in the understanding of complex, strongly interacting and disordered systems, more specifically on their dynamical response. This will have an impact on the development of novel theories to cover some of the presently existing knowledge gaps and will prompt advanced applications of the investigated materials. Liquid metals are a prototypical example of complex systems extensively studied from the sixties on, now re-emerging as powerful functional materials for unconventional and broad spectrum applications. Research on liquid metal composites will benefit of the new experimental possibilities available at the ESS. We review the status of the experiments on liquid metals dynamics, focusing on a selected set of systems, and discuss the perspectives for cutting-edge experiments at the new sources. Graphical abstract