Lifeboat Foundation

By strategically straining materials that are as thin as a single layer of atoms, University of Rochester scientists have developed a new form of computing memory that is at once fast, dense, and low-power. The researchers outline their new hybrid resistive switches in a study published in Nature Electronics.

Developed in the lab of Stephen M. Wu, an assistant professor of electrical and computer engineering and of physics, the approach marries the best qualities of two existing forms of resistive switches used for memory: memristors and phase-change materials. Both forms have been explored for their advantages over today’s most prevalent forms of memory, including dynamic random access memory (DRAM) and flash memory, but they have their drawbacks.

Wu says that memristors, which apply voltage to a thin filament between two electrodes, tend to suffer from a relative lack of reliability compared to other forms of memory. Meanwhile, phase-change materials, which involve selectively melting a material into either an amorphous state or a crystalline state, require too much power.

How many fundamental forces are there in our universe? For particle physicists, answering this question can be tricky.

Of course, there’s the force of gravity, which keeps us from floating out of our seats. There’s also the strong nuclear force, which glues the nuclei of our atoms together. Then there’s the electromagnetic force, which is where we get electric currents and magnetic fields. And there’s the weak nuclear force, which mediates radioactive decay.

We’re up to four forces, right?

Scientists have revealed how lattice vibrations and spins talk to each other in a hybrid excitation known as an electromagnon. To achieve this, they used a unique combination of experiments at the X-ray free electron laser SwissFEL. Understanding this fundamental process at the atomic level opens the door to ultrafast control of magnetism with light.

Within the atomic lattice of a solid, particles and their various properties cooperate in wave-like motions known as collective excitations. When atoms in a lattice jiggle together, the collective excitation is known as a phonon. Similarly, when the atomic spins—the magnetization of the atoms-move together, it’s known as a magnon.

The situation gets more complex. Some of these collective excitations talk to each other in so-called hybrid excitations. One such hybrid excitation is an electromagnon. Electromagnons get their name because of the ability to excite the atomic spins using the electric field of light, in contrast to conventional magnons: an exciting prospect for numerous technical applications. Yet their secret life at an atomic level is not well understood.

Entanglement is a quantum phenomenon where the properties of two or more particles become interconnected in such a way that one cannot assign a definite state to each individual particle anymore. Rather, we have to consider all particles at once that share a certain state. The entanglement of the particles ultimately determines the properties of a material.

“Entanglement of many particles is the feature that makes the difference,” says Christian Kokail, one of the first authors of the paper published in Nature. “At the same time, however, it is very difficult to determine.”

The researchers led by Peter Zoller at the University of Innsbruck and the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences (ÖAW) now provide a new approach that can significantly improve the study and understanding of entanglement in quantum materials.

A small team of chemists from Nankai University, Nanjing Tech University and Shanxi University, all in China, working with a colleague from Universidad San Sebastián, in Chile, has, for the first time, created a fullerene-like molecule made entirely of metal atoms.

In their paper published in the journal Science, the group describes how they created the molecule by accident while they were conducting research experiments with antimony, potassium and gold atoms.

A fullerene is a form of carbon where its molecules are connected by single and double bonds which result in the formation of a closed cage-like structure. It was first realized in 1985 and since that time analogous inorganic fullerenes have been created using a variety of compounds. But until now, none of them have been purely metal.

In the search for new particles and forces in nature, physicists are on the hunt for behaviors within atoms and molecules that are forbidden by the tried-and-true Standard Model of particle physics. Any deviations from this model could indicate what physicists affectionately refer to as “new physics.”

Caltech assistant professor of physics Nick Hutzler and his group are in pursuit of specific kinds of deviations that would help solve the mystery of why there is so much matter in our universe. When our universe was born about 14 billion years ago, matter and its partner, antimatter, are believed to have existed in equal measure.

Typically, matter and antimatter cancel each other out, but some kind of asymmetry existed between the different types of particles to cause matter to win out over antimatter. Hutzler’s group uses tabletop experiments to look for symmetry violations—the deviant particle behaviors that led to our lopsided matter-dominated universe.

Over centuries of painstaking laboratory work, chemists have synthesized several hundred thousand inorganic compounds — generally speaking, materials not based on the chains of carbon atoms that are characteristic of organic chemistry. Yet studies suggest that billions of relatively simple inorganic materials are still waiting to be discovered³. So where to start looking?

Many projects have tried to cut down on time spent in the lab tinkering with various materials by computationally simulating new inorganic materials and calculating properties such as how their atoms would pack together in a crystal. These efforts — including the Materials Project based at the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California — have collectively come up with about 48,000 materials that they predict will be stable.

Google DeepMind has now supersized this approach with an AI system called graph networks for materials exploration (GNoME). After training on data scraped from the Materials Project and similar databases, GNoME tweaked the composition of known materials to come up with 2.2 million potential compounds. After calculating whether these materials would be stable, and predicting their crystal structures, the system produced a final tally of 381,000 new inorganic compounds to add to the Materials Project database¹.

Northwestern University researchers have raised the standards again for perovskite solar cells with a new development that helped the emerging technology hit new records for efficiency.

The findings, published today (Nov. 17) in the journal Science, describe a dual-molecule solution to overcoming losses in efficiency as sunlight is converted to energy. By incorporating first, a molecule to address something called surface recombination, in which electrons are lost when they are trapped by defects—missing atoms on the surface, and a second molecule to disrupt recombination at the interface between layers, the team achieved a National Renewable Energy Lab (NREL) certified efficiency of 25.1% where earlier approaches reached efficiencies of just 24.09%.

“Perovskite solar technology is moving fast, and the emphasis of research and development is shifting from the bulk absorber to the interfaces,” said Northwestern professor Ted Sargent. “This is the critical point to further improve efficiency and stability and bring us closer to this promising route to ever-more-efficient solar harvesting.”

Researchers investigate whether dark matter particles actually are produced inside a jet of standard model particles.

The existence of dark matter is a long-standing puzzle in our universe. Dark matter makes up about a quarter of our universe, yet it does not interact significantly with ordinary matter. The existence of dark matter has been confirmed by a series of astrophysical and cosmological observations, including in the stunning recent pictures from the James Webb Space Telescope. However, up to date, no experimental observation of dark matter has been reported. The existence of dark matter has been a question that high energy and astrophysicists around the world have been investigating for decades.

Advancements in Dark Matter Research.