As scientists continue to push the boundaries of what is possible, they stumble upon unexpected discoveries that challenge our understanding of the world. A recent breakthrough at the SLAC National Accelerator Laboratory has revealed the secret chemistry of gold, a metal once thought to be unreactive and boring. Researchers have successfully formed solid binary gold hydride, a compound made exclusively of gold and hydrogen atoms, under extreme conditions.

The team led by Mungo Frost, staff scientist at SLAC, was studying how hydrocarbons form diamonds under high pressure and heat. In their experiments at the European XFEL in Germany, they embedded gold foil into the samples to absorb X-rays and heat the weakly absorbing hydrocarbons. To their surprise, they not only observed the formation of diamonds but also discovered the formation of gold hydride.

“It was unexpected because gold is typically chemically very boring and unreactive — that’s why we use it as an X-ray absorber in these experiments,” said Mungo Frost. “These results suggest there’s potentially a lot of new chemistry to be discovered at extreme conditions where the effects of temperature and pressure start competing with conventional chemistry, and you can form these exotic compounds.”

The research team used a diamond anvil cell to squeeze hydrocarbon samples to pressures greater than those within Earth’s mantle and then heated them to over 3,500 degrees Fahrenheit using X-ray pulses from the European XFEL. This allowed them to resolve the structural transformations within the samples and observe how the gold lattice scattered X-rays.

The team found that under these extreme conditions, hydrogen was in a dense, superionic state, flowing freely through the gold’s rigid atomic lattice and increasing its conductivity. This phenomenon is not directly accessible through other experimental means, but studying it could provide new insights into nuclear fusion processes inside stars like our sun and help develop technology to harness fusion energy on Earth.

The discovery of gold hydride also opens up new avenues for exploring chemistry at extreme conditions. Gold, once thought to be unreactive, was found to form a stable compound with hydrogen under high pressure and temperature. This suggests that more research is needed to understand the properties of materials under these extreme conditions.

In addition to their findings on gold hydride, the team also developed simulation tools that could model other exotic material properties in extreme conditions. These tools have the potential to be applied beyond this specific study, offering new opportunities for researchers to explore and understand complex phenomena.

The research was conducted by an international team of scientists from SLAC National Accelerator Laboratory, European XFEL, DESY, Rostock University, Frankfurt University, Bayreuth University, Carnegie Institution for Science, Stanford University, and the Stanford Institute for Materials and Energy Sciences (SIMES). The work was supported by the DOE Office of Science.

Unveiling a Secret Material from Meteorites: A Hybrid Crystal-Glass that Defies Heat

Imagine a material that can withstand extreme temperature fluctuations without losing its shape or structure. Such a material would have revolutionary implications for various industries, from aerospace and electronics to energy and steel production. Researchers at Columbia Engineering have made a groundbreaking discovery by identifying a hybrid crystal-glass material in meteorites, which exhibits unprecedented thermal properties.

The problem of optimizing the performance and durability of materials used in different applications essentially boils down to understanding how their chemical composition and atomic structure determine their heat-conduction capabilities. Michele Simoncelli, an assistant professor at Columbia Engineering, has tackled this issue from first principles by leveraging machine-learning techniques and traditional first-principles methods to solve them with quantitative accuracy.

In research published in the Proceedings of the National Academy of Sciences, Simoncelli and his collaborators predicted the existence of a material with hybrid crystal-glass thermal properties. A team of experimentalists led by Etienne Balan confirmed this prediction with measurements, discovering that the first-of-its-kind material was present in meteorites and had also been identified on Mars.

The fundamental physics driving this behavior could advance our understanding and design of materials that manage heat under extreme temperature differences. This discovery may provide insight into the thermal history of planets, opening new avenues for research.

Thermal conduction depends on whether a material is crystalline or glassy, with opposite trends observed in crystals and glasses. In 2019, Simoncelli, Nicola Marzari, and Francesco Mauri derived a single equation that captures this behavior. Using this equation, they investigated the relationship between atomic structure and thermal conductivity in materials made from silicon dioxide.

They predicted that a particular “tridymite” form of silicon dioxide would exhibit the hallmarks of a hybrid crystal-glass material with a thermal conductivity that remains unchanged with temperature. This unusual thermal-transport behavior bears analogies with the invar effect in thermal expansion, for which the Nobel Prize in Physics was awarded in 1920.

The team obtained special permission from the National Museum of Natural History in Paris to perform experiments on a sample of silica tridymite carved from a meteorite that landed in Steinbach, Germany, in 1724. Their experiments confirmed their predictions: meteoric tridymite has an atomic structure that falls between an orderly crystal and disordered glass, and its thermal conductivity remains essentially constant over the experimentally accessible temperature range of 80 K to 380 K.

Upon further investigation, the team predicted that this material could form from decade-long thermal aging in refractory bricks used in furnaces for steel production. Steel is one of the most essential materials in modern society, but producing it is carbon-intensive: just 1 kg of steel emits approximately 1.3 kg of carbon dioxide, with the nearly 1 billion tons produced each year accounting for about7% of carbon emissions in the U.S.

Materials derived from tridymite could be used to more efficiently control the intense heat involved in steel production, helping to reduce the steel industry’s carbon footprint. Future research is shaping emerging technologies, including wearable devices powered by thermoelectrics, neuromorphic computing, and spintronic devices that exploit magnetic excitations for information processing.

Simoncelli’s group at Columbia is exploring these topics, structured around three core pillars: the formulation of first-principles theories to predict experimental observables, the development of AI simulation methods for quantitatively accurate predictions of materials properties, and the application of theory and methods to design and discover materials to overcome targeted industrial or engineering challenges.

In a groundbreaking breakthrough, researchers from New Jersey Institute of Technology (NJIT) have successfully employed artificial intelligence to identify five powerful new materials that could potentially replace traditional lithium-ion batteries. These innovative discoveries were made possible through the application of generative AI techniques to rapidly explore thousands of material combinations.

Unlike conventional lithium-ion batteries, which rely on lithium ions carrying a single positive charge, multivalent-ion batteries use elements such as magnesium, calcium, aluminum, and zinc whose ions carry two or even three positive charges. This unique property allows multivalent-ion batteries to potentially store significantly more energy, making them highly attractive for future energy storage solutions.

However, the greater size and electrical charge of multivalent ions make it challenging to accommodate them efficiently in battery materials – a hurdle that the NJIT team’s new AI-driven research directly addresses. “One of the biggest hurdles wasn’t a lack of promising battery chemistries – it was the sheer impossibility of testing millions of material combinations,” said Professor Dibakar Datta, leading researcher on the project.

To overcome this obstacle, the NJIT team developed a novel dual-AI approach: a Crystal Diffusion Variational Autoencoder (CDVAE) and a finely tuned Large Language Model (LLM). These AI tools rapidly explored thousands of new crystal structures, something previously impossible using traditional laboratory experiments.

The CDVAE model was trained on vast datasets of known crystal structures, enabling it to propose completely novel materials with diverse structural possibilities. Meanwhile, the LLM was tuned to zero in on materials closest to thermodynamic stability, crucial for practical synthesis. “Our AI tools dramatically accelerated the discovery process, which uncovered five entirely new porous transition metal oxide structures that show remarkable promise,” said Datta.

The team validated their AI-generated structures using quantum mechanical simulations and stability tests, confirming that the materials could indeed be synthesized experimentally and hold great potential for real-world applications. Datta emphasized the broader implications of their AI-driven approach: “This is more than just discovering new battery materials – it’s about establishing a rapid, scalable method to explore any advanced materials, from electronics to clean energy solutions, without extensive trial and error.”

With these encouraging results, Datta and his colleagues plan to collaborate with experimental labs to synthesize and test their AI-designed materials, pushing the boundaries further towards commercially viable multivalent-ion batteries. This exciting breakthrough has the potential to revolutionize the field of energy storage, paving the way for a more sustainable future.