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Category: materials

A Hall ‘rectenna’ can detect signals over a 100 GHz frequency range

Many current wireless communication, imaging and sensing technologies rely on components that convert oscillating electric and magnetic fields (i.e., electromagnetic waves) into electrical signals. Some of the most used components are so-called p-n diodes, semiconducting devices that combine two types of materials with distinct electrical properties.

In conventional diode designs, the conversion of electromagnetic waves into electrical signals relies on the nonlinear transport of electrons. This means that the electric current in the devices does not change proportionally with the voltage applied, which allows them to rectify signals (i.e., convert alternating current into direct current) and combine signals with different frequencies.

A key limitation of traditional diodes is that thermal effects introduce noise, causing electrons to move randomly and making weak signals harder to detect. Moreover, electrons typically take a finite time to travel across the device, also known as the transit time, which limits the performance of the diodes at very high frequencies.

Superconducting altermagnets could carry spin without energy loss

Researchers have proposed that a newly identified class of magnetic materials could extend the zero-resistance currents of superconductors to electron spins. Publishing their calculations in Physical Review X, Kyle Monkman and colleagues at the University of British Columbia propose how “altermagnets” could enable persistent spin currents to flow without dissipation. If confirmed experimentally, the effect could provide a powerful new platform for spintronics, where information is encoded in spin rather than electric charge.

The ability to transport spins over long distances is a central challenge in spintronics. In conventional metals and semiconductors, spin currents decay rapidly due to effects that randomize electron spins. One promising workaround has been superconducting spintronics, where dissipationless charge transport is combined with magnetic materials. However, these hybrid systems often suffer from intrinsic drawbacks, including stray magnetic fields that can interfere with nearby components, suppressing superconductivity.

First confirmed in 2024, altermagnets offer a potential way around these problems. Like antiferromagnets (where a magnetic dipole’s spin is always opposite to those of its neighbors), they have zero net magnetization, avoiding unwanted magnetic fields.

Physicists find electronic agents that govern flat band quantum materials

Physicists have directly visualized the fundamental electronic building blocks of flat-band quantum materials, a class of systems in which electron motion is effectively quenched and strong interactions give rise to emergent phases of matter. In a study published in Nature Physics, Qimiao Si’s group at Rice University, in collaboration with researchers at the Weizmann Institute of Science, identified compact molecular orbitals that act as the key electronic agents governing the exotic behavior of these materials.

“In flat band materials, electron motion experiences destructive interference,” said Si, the Harry C. and Olga K. Wiess Professor of Physics and Astronomy and director of Rice’s Extreme Quantum Materials Alliance.

These flat band materials are also topological with properties that are preserved as the material continuously bends or stretches in any symmetry-preserving way.

Next-generation memory material has the surprising property of shrinking when heated

Most materials we use in everyday life expand slightly when heated and return to their original size when cooled. In addition to such thermal properties, materials can also have electrical properties or magnetic properties, and traditionally we have used these characteristics separately. However, some materials allow multiple properties to coexist within a single substance.

Research on such materials is expected to contribute to the development of next-generation memory devices that can store and retain information while consuming far less energy.

How multiferroics could transform memory A representative example is a class of materials known as multiferroics, which combine the properties of a capacitor (the ability to store electric charge) and a magnet. Among them, bismuth ferrite (BiFeO₃) is one of the most intensively studied materials in the field. When an external voltage is applied, the direction of its stored electric polarization can be switched, and this change can also influence its magnetic properties.

AI data centers need faster links: A mass-producible optical microchip could help

Researchers at Karlsruhe Institute of Technology (KIT) and École Polytechnique Fédérale de Lausanne (EPFL) present a novel component that enables very fast, economical, and reliable data transmission thanks to an advanced manufacturing technology. Their new electro-optical modulator transmits data efficiently through fiber-optic cables and can be manufactured inexpensively in large quantities on standard semiconductor wafers. This is important, as AI applications and growing data traffic are pushing data centers and fiber-optic networks to their performing limits. The researchers present their findings in Nature Communications.

Similar to modern computer chips, the modulator can be manufactured using established semiconductor processes. The researchers combine lithium tantalate —a material that guides light particularly well and serves as the heart of the modulator—with a proven chip manufacturing technique from microelectronics. To date, these two technologies have never been used together. For the first time now, they enable reliable mass production.

Durum wheat lines combine freezing tolerance with high pasta quality

Researchers from Skoltech, the International Maize and Wheat Improvement Center in Mexico, the Research Center for Cereal and Industrial Crops in Italy, and other international organizations have developed new durum wheat lines capable of surviving freezing temperatures while maintaining the grain quality required for premium pasta production. The study, published in Frontiers in Plant Science, presents a new breeding framework that could help make durum wheat production more resilient to climate variability.

Durum wheat is the primary raw material used to produce pasta worldwide, yet it remains highly vulnerable to sudden freezing events. As climate variability increases, unpredictable cold spells pose a growing risk to wheat production. At the same time, breeders must preserve the high gluten quality that gives pasta its characteristic texture and cooking properties.

This “Quantum” Material Fooled Scientists — but It’s Actually Something Even Stranger

A material thought to be a quantum spin liquid actually exhibits a newly identified magnetic state caused by competing ferromagnetic and antiferromagnetic interactions. Materials that enter a quantum spin liquid phase attract significant attention because of their unusual properties and potential

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