The scientific case for concurrent neutron and X-ray scattering and spectroscopy

The interrogation of materials with X-rays or neutrons to determine the structure, energetics, and dynamics of materials is fundamental to advancing materials' physical and chemical science and developing innovative material technologies. A transcending challenge in developing novel materials is that progress hinges on understanding the structure and dynamics across multiple time and length scales in complex materials that feature multiple components, interfaces, and compositions. Despite the ever-growing demands on materials’ characterization, existing approaches are almost exclusively based on isolated X-ray or neutron scattering, i.e., an approach commensurate with the more narrowly defined needs of fifty years ago. A three-day workshop sponsored by the U.S. National Science Foundation (NSF) analyzed the demand for concurrent neutron and X-ray (NeX) experiments. It was held at the Spring Hill Suites, San Jose, California, from June 2 to 4, 2022. In this workshop, 70 national and international experts ascertained the crucial need to establish NeX capabilities to advance the science of complex materials and systems in the US. Here, we illustrate the need for NeX scattering and spectroscopy experiments by showcasing examples that span areas as diverse as biomaterials, energy science, soft matter, and nanomaterials. To provide NeX capability will require new instrumentation that enables concurrent experiments. Affected areas include chemistry, soft matter, quantum materials, pure and applied chemistry, bioscience, geoscience, and applied materials. NeX benefits research outcomes due to the complementarity of the two techniques, which is essential for better model refinement. While joint refinement of data from separate neutron and X-ray experiments is critical to avoid ambiguities, especially in multiphase-multicomponent materials, concurrent experiments overcome scientific and technical barriers associated with single measurements, separated by location and, thus, time. Among all the examples, these factors introduce uncertainties in the results that complicate data analysis. [1,2] [3] While models are strongly sample-dependent, the principles of joint refinement are generally applicable to these disciplines, including the development of advanced parameterization, modeling, and analysis techniques that also consider the temporal and spatial resolutions of the two methods, leading to unambiguous data interpretation. Solutions for technical barriers must be found to realize NeX experiments, including developing robust sample environments that meet the optical requirements of neutrons and X-rays.

This themed issue explores the different length and timescales that determine the physics and chemistry of a variety of key of materials, explored from the perspective of a wide range of disciplines, including physics, chemistry materials science, Earth science and biochemistry. The topics discussed include catalysis, chemistry under extreme conditions, energy materials, amorphous and liquid structure, hybrid organic materials and biological materials. The issue is in two parts, with this second set of contributions exploring hybrid organic materials, catalysis low-dimensional and graphitic materials, biological materials and naturally occurring, super-hard material as well as dynamic high pressure and new developments in imaging techniques pressure.This article is part of the theme issue 'Exploring the length scales, timescales and chemistry of challenging materials (Part 2)'.

Advances in Soft Functional Materials Research

Project Summary Company: Adelphi Technology, Inc. Title: Universal Neutron Spin Flipper PI: Dr. Jay Theodore Cremer Topic: 17. Instrumentation and Tools for Materials Research Using Neutron Scattering Subtopic: b. Beam Conditioning Optics Statement of the problem or situation that is being addressed. A recent report by the Basic Energy Sciences Advisory Committee entitled “The Scientific Justification for a U.S. Domestic High-Performance Reactor-Based Research Facility” points out that polarized neutrons are increasingly being used to obtain scientific results not available to any other methods in areas as diverse as topological quantum materials, functional materials, soft matter, and biological materials. Because of the importance of polarized neutrons, more than half of the instruments planned for initial deployment at the Spallation Neutron Source (SNS) Second Target Station (STS) will use polarized neutrons as will 12 of the first 15 instruments planned at the European Spallation Source (ESS). Additional instrumentation using polarized neutrons is also planned for the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). General statement of how this problem is being addressed. Devices to rotate neutron polarization through either 180 or 90, called flippers, are ubiquitous components of all polarized neutron instruments. While several different devices are currently used for these purposes, there is a need both for higher efficiency and for flippers that can be incorporated easily into recently developed instrumentation that uses polarization neutrons to expand scientific research. Such instrumentation, including the magnetic Wollaston prisms developed by the Adelphi/Indiana team, are now being employed by researchers at the HFIR at ORNL for important research into novel quantum materials and in other areas. We believe that the technology we developed for the Wollaston prisms will allow us to design components that can be assembled into the various types of flipper needed for almost all polarized neutron experiments. Commercial Applications and Other Benefits In view of the increasing demand for polarized neutrons and the unique scientific information they can provide, we expect several major instrumentation upgrades at both U.S. and foreign neutron centers will require high-efficiency polarized-neutron components over the coming decade, creating a market for the devices we will design. These components will enhance scientists’ abilities to probe both the spatial and time dependence of density fluctuations in a wide range of quantum and multi-scale materials. As stated in the BESAC report cited above, polarized neutrons will “uniquely resolve the complex structures of topological and multiferroic materials” that will underpin the coming revolution in quantum computing and communication. Summary for Members of Congress Neutron beams are a powerful materials-science probe that provide unique information about the structure of matter. The proposed devices will accelerate scientific discoveries required to achieve national goals for quantum computation and communication.

EXPANSE, an EXPanded Angle Neutron Spin Echo instrument, has been proposed and selected as one of the first suite of instruments to be built at the Second Target Station of the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is designed to address scientific problems that involve high-energy resolution (neV-μeV) of dynamic processes in a wide range of materials. The wide-angle detector banks of EXPANSE provide coverage of nearly two orders of magnitude in scattering wavenumbers, and the wide wavelength band affords approximately four orders of magnitude in Fourier times. This instrument will offer unique capabilities that are not available in the currently existing neutron scattering instruments in the United States. Specifically, EXPANSE will enable direct measurements of slow dynamics in the time domain over wide Q-ranges simultaneously and will also enable time-resolved spectroscopic studies. The instrument is expected to contribute to a diverse range of science areas, including soft matter, polymers, biological materials, liquids and glasses, energy materials, unconventional magnets, and quantum materials.

Electrochemical energy materials are those used in electrochemical energy conversion and storage technologies, such as batteries, fuel cells, and electrochemical capacitors. Their development is complicated by the fact that they must simultaneously satisfy a diverse set of design criteria, which in turn depend on multiple, interacting physical processes occurring across multiple length and time scales. An energy material’s microstructure adds to its complexity: in addition to occurring across multiple length and time scales, the physical processes that determine its performance also occur within a geometrically complex, often 3-D, domain. Then, if one wishes to integrate molecular-scale knowledge (e.g., from molecular dynamics simulations, etc.) into a multi-scale design framework, it would be advantageous to have a robust, computationally inexpensive means of accounting for the geometrical complexity of a typical energy material microstructure. In this work, we consider energy material microstructures comprised of interwoven, 3-D networks and present a heuristic, fully analytical model – the Analytical Transport Network (ATN) Model – that explicitly relates the morphology and topology of a given network’s channels to its effective transport coefficient and, in an approximate manner, its electrochemical activity. ATN’s effective transport coefficient estimates obtained for conserved flow within a set of artificially-generated and real energy material microstructures exhibited good agreement with those obtained from electrochemical fin theory and finite element analysis, but were computed 1.5 and 6 orders of magnitude faster, respectively. In addition, the theory explicitly relates a number of morphological and topological parameters directly to the effective transport coefficient, whereby the distributions that characterize the structure are readily available for, e.g., morphological/topological optimization studies or further topological characterization by network science. In considering reacting flow, the ATN model is used to identify morphological and topological features that influence the flow consumed by reactions per the flow entering the network. In this talk, we will present the ATN model, compare its predictions to those from existing techniques as well as to experimental measurements, and discuss how it can potentially be extended to elucidate the influence of channel morphology and topology on multi-component and transient flow.

<p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="first" dir="auto" id="d6315e44">Electron-optical beam lines have undergone evolutional growth in their capabilities over the last 50 years. Partially this has been the result of the evolution of our basic instrumentation, a contributing factor has also been major advances in ancilliary systems, and importantly a significant advancement has been due to our ability to design and execute computationally mediated experiments. This nexus of developments has given us modern electron-optical systems with unprecedented capabilities for characterizing the nature of both hard and soft materials from macroscopic to the sub-atomic regime. We have spent significant effort understanding the physics of electron-solid interactions and from that interpreting images, diffraction, and spectroscopy. Today we continue to push, and advance, the limits of technology to elucidate an every growing range of research challenges. <p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" dir="auto" id="d6315e46">A selection of studies will be used to illustrate how today’s capabilities can been used as well as their corresponding challenges/limitations using a variety of exemplars including: the nature of interfaces and ion beam irradiation defects in crystalline solids, probing the organic/inorganic elemental interfaces, noble metal incorporation to nanoscale materials for enhancing photocatalysis, as well as in the challenges of characterization of today’s energy and quantum materials.

Directly correlating lifetime to coating composition by using standardized, artificial exposures, or even natural exposure, is often very difficult. However, significant progress can be made by breaking down the problem into smaller questions, which can be separately addressed. If one understands the physical parameters that affect end-use properties, then one can also group, and thus correlate, properties according to whether they depend on processes at the surface or in the bulk of a coating, or whether they depend on defects. A scheme is presented that shows how one can use knowledge from analytical physical or chemical materials science in a statistical model related to the “chemical paradigm.” Simple physical models that use this information, about the initial state of the coating and its rate of degradation, can be used to compare the performance of coatings and estimate, simply, service lifetime depending on the property of interest, in the environment of interest. One can see that different properties are sensitive in different ways to the degradation process and decay with a different rate. Thus, although properties may be determined by the same degradation process, and location within a coating, they do not correlate directly. These approaches show how to organize our knowledge of degradation processes, and environments, and be able to make some testable predictions on how coating properties deteriorate.

Ultrafast vibrational and electronic spectroscopy unravels the dynamics underlying the functionality of quantum, energy, and biological materials. To understand and ultimately control the processes that underly the emergent function in these materials requires imaging the elementary excitations on their natural time and length scales. To achieve this goal, we have developed scanning probe microscopy with ultrafast and shaped laser pulse excitation for multiscale spatio-temporal optical nano-imaging. However, mostly limited to short-lived transient states, the contrast obtained has remained insufficient to probe important weak and long-lived excitations such as low-conductivity carriers, molecular vibrations, lattice phonons, and their couplings. Here, we demonstrate ultrafast heterodyne pump-probe (HPP) nano-imaging to simultaneously resolve quantum dynamics in space, time, and frequency. In ultrafast infrared nano-imaging based on excitation modulation and sideband detection we isolate and selectively characterize excited-state electron and vibration dynamics from femto- do micro-second times scales. In exemplary applications I will show ultrafast movies to resolve the fundamental quantum dynamics from the few-femtosecond coherent to the thermal transport regime. Specifically, in quantum materials, in ultrafast nano-imaging of photoinduced carrier and phase behavior we identify distinct transient nano-domain behavior revealing competing electronic and lattice degrees of freedom. Further in lead halide perovskites from transient vibrational nano-FTIR imaging we resolve excited state polaron dynamics and polaron-cation coupling underlying their photovoltaic response. Lastly, by simultaneous probing of carrier dynamics and interfacial phonon softening we establish nano-thermometry to imagine interfacial thermal transport dynamics in 2D semiconductor/insulator heterostructures. These examples show how HPP nano-imaging opens the door to elementary processes and interactions in functional materials with full spatio-temporal-spectral resolution.

Abstract. Aim. An important direction in contemporary concrete science is aimed at the development of multicomponent systems using mineral powder fillers in a finely dispersed state to create strong and durable building composites. One of the most significant factors affecting the properties of multicomponent systems is the compatibility of its components. Efforts on the part of leading scientific institutes are aimed at replacing expensive and energy-intensive Portland cement with composite concrete products produced using mixed binders. In this context, the development of modern effective composites based on clinkerless alkaline binders becomes an urgent problem. Methods. Studies into the compatibility of multicomponent cementing systems are based on a contemporary technological approach that contributes to the production of strong and durable cement stone, without the use of traditional Portland cement. Results. Electron probe studies and X-ray phase analysis of concrete produced using a clinker-free alkaline activation binder showed that the studied multicomponent system contains a hydro-aluminosilicate zeolite phase of variable composition, as well as indicating the presence of calcite, quartz, albite feldspar, mica, zeolites and potassium feldspar. Conclusion. The results of the studies confirm the compatibility of all components of the multicomponent system comprised of mineral powder, alkaline coater and surfactant. The proposed technological method can be used to produce strong and durable building composites with clinker-free technology avoiding the use of expensive and energy-intensive Portland cement. Acknowledgments. The work was performed as part of research on the implementation of scientific project No. 05.607.21.0320. “Development of technology for new building composites on clinker-free alkaline binders using substandard natural and secondary raw materials” which received support from the federal target program “Research and Development in Priority Directions for the Development of the Russian Science and Technology Complex for 2014-2020.” Unique identifier for the agreement RFMTFI60719X0320.

Imagine future computers that can perform calculations a million times faster than today’s most powerful supercomputers at only a tiny fraction of the energy cost. Imagine power being generated, stored, and then transported across the national grid with nearly no loss. Imagine ultrasensitive sensors that keep us in the loop on what is happening at home or work, warn us when something is going wrong around us, keep us safe from pathogens, and provide unprecedented control of manufacturing and chemical processes. And imagine smart windows, smart clothes, smart buildings, supersmart personal electronics, and many other items — all made from materials that can change their properties “on demand” to carry out the functions we want. The key to attaining these technological possibilities in the 21st century is a new class of materials largely unknown to the general public at this time but destined to become as familiar as silicon. Welcome to the world of quantum materials — materials in which the extraordinary effects of quantum mechanics give rise to exotic and often incredible properties. To realize the tantalizing potential of quantum materials, there is much basic scientific research to be done. Recognizing the high potential impact of quantum materials, nations around the world are already investing in this effort. We must learn how the astonishing properties of quantum materials can be tailored to address our most pressing technological needs, and we must dramatically improve our ability to synthesize, characterize, and control quantum materials. To accelerate the progress of quantum materials research, the U.S. Department of Energy’s Office of Science, Office of Basic Energy Sciences (BES), sponsored a “Basic Research Needs Workshop on Quantum Materials for Energy-relevant Technology,” which was held near Washington, D.C. on February 8–10, 2016. Attended by more than 100 leading national and international scientific experts in the synthesis, characterization, and theory of quantum materials, the workshop identified four priority research directions (PRDs) that will lay the foundation to better understand quantum materials and harness their rich technological potential.

The field of quantum materials has experienced rapid growth over the past decade, driven by exciting new discoveries with immense transformative potential. Traditional synthetic methods to quantum materials have, however, limited the exploration of architectural control beyond the atomic scale. By contrast, soft matter self-assembly can be used to tailor material structure over a large range of length scales, with a vast array of possible form factors, promising emerging quantum material properties at the mesoscale. This review explores opportunities for soft matter science to impact the synthesis of quantum materials with advanced properties. Existing work at the interface of these two fields is highlighted, and perspectives are provided on possible future directions by discussing the potential benefits and challenges which can arise from their bridging.

Chirality exists as a ubiquitous phenomenon in nature, from molecular level l-amino acids, d-sugar, secondary structures of proteins, DNA, RNA, and nanoscale helices to macroscopic conch and even galaxy. The aggregation of molecular building blocks with or without chiral centers might bring about asymmetric spatial stacking, which further results in the appearance of nonsymmetry in extended scales like helical nanofibers. This phenomenon, known as supramolecular chirality, is an important branch of supramolecular and self-assembly chemistry, which relates intimately with biomimetics, asymmetric catalysis, and designing chiroptic advanced materials. One of the important research focuses among supramolecular chirality is about rational manipulation of chirality amplification and handedness, presenting a profound influence on the performance of resulting soft materials such as circularly polarized luminescence and cell adhesion on hydrogels. The control over supramolecular chirality normally relies on two factors, i.e., thermodynamic and kinetic variables dependent on molecular structural parameters and environmental contributions, respectively. Supramolecular chirality in two or more component-based systems places an emphasis on thermodynamic control as it occurs from either integrated coassembly or separated self-sorting, which is more sophisticated than that of single component systems. Thus, the study on supramolecular chirality in multicomponent systems could mimic complicated biosystems, allowing for better understanding about the origin of natural chirality and extended applications as biomimetics. To date, the exploration of supramolecular chirality in multicomponent systems is restricted on both fundamental and application aspects when compared to more matured single component systems. Over the past few years, we have carried out systematic studies on several systems expressing supramolecular chirality from chiral amplification or symmetry breaking. We emphasized more the thermodynamic control by introducing a second component to form noncovalent bonding like hydrogen bonding or coordination interactions. In this Account, we would specifically discuss rational manipulation of the occurrence, transfer, and inversion of supramolecular chirality by taking several of the latest representative examples. In the multicomponent systems, in addition to the building blocks with chiral centers, the second or third components could be structural analogues and achiral small molecules such as bipyridines, melamine, metal ions, inorganic nanomaterials, and even solvents. These second or third components are able to incorporate during the aggregation to form coassembly via noncovalent bonds, influencing spatial arrangements of building blocks within various dimensions from vesicles and nanofibers to organic/inorganic hybrids. Other than chirality, morphology, stimulus responsiveness, and properties could also be well tailored by controlling interactions between different components.

Neutron sources have an important role to play in the development of new materials for storing sustainable energy, allowing researchers to gain deeper insights into their functionality. We spoke to Professor Elizabeth Blackburn about how she and her team are using neutron scattering techniques to investigate energy and quantum materials.

Since the pioneering neutron diffraction experiments by Ernest O. Wollan and Clifford G. Shull in the 1940s, Oak Ridge National Laboratory (ORNL) has played a central role in the advancement of single-crystal diffraction techniques. Over the past 75 years, ORNL's contributions have significantly shaped structural science across a range of disciplines, especially in chemistry, condense matter physics and materials science.Among the suite of single-crystal diffractometers at the High Flux Isotope Reactor (HFIR) and the Spallation Neutron Source (SNS), the TOPAZ instrument plays a central role in extending neutron crystallography beyond traditional three-dimensional frameworks. By combining neutron wavelength-resolved Laue diffraction with event-based neutron detection, TOPAZ enables simultaneous measurement of three-dimensional diffraction space and real-time tracking of structural responses to external stimuli in parameter space—including temperature, pressure, and applied fields. These capabilities are particularly valuable for investigating hydrogen bonding in functional energy materials, local and short-range correlations in quantum materials, and structural and magnetic phase transitions under operando conditions.Looking ahead, the integration of artificial intelligence (AI) and machine learning (ML) into neutron diffraction workflows is expected to enhance data interpretation, support real-time experimental optimization, and enable adaptive exploration of complex structural systems. These developments will broaden the scope of crystallographic research in structural science and create new opportunities for discovery in the study of advanced energy and quantum materials.