Researchers from the Institute of Metal Research (IMR) of the Chinese Academy of Sciences have developed a new ferroelectric ultraviolet photodetector material that overcomes the long-standing performance limitations of conventional photodetectors.
This breakthrough, published in Nature Communications, promises to enable next-generation optical detection with ultra-fast speed, high sensitivity, and low noise across a wide range of applications.
Photodetectors convert light signals into electrical currents and are fundamental to modern optoelectronics. They are essential for technologies such as high-speed optical communications, environmental monitoring, and space exploration. However, creating a material that possesses all three of these qualities has been a significant challenge.
Building things so small that they are smaller than the width of a human hair was previously achieved by using a method called two-photon polymerization, also known as 2PP—today’s state-of-the-art in 3D micro- and nanofabrication. Tiny sculptures such as a miniature replica of the Eiffel Tower or the Taj Mahal made the headlines.
In its first moments, the infant universe was a trillion-degree-hot soup of quarks and gluons. These elementary particles zinged around at light speed, creating a “quark-gluon plasma” that lasted for only a few millionths of a second. The primordial goo then quickly cooled, and its individual quarks and gluons fused to form the protons, neutrons, and other fundamental particles that exist today.
Physicists at CERN’s Large Hadron Collider in Switzerland are recreating quark-gluon plasma (QGP) to better understand the universe’s starting ingredients. By smashing together heavy ions at close to light speeds, scientists can briefly dislodge quarks and gluons to create and study the same material that existed during the first microseconds of the early universe.
Now, a team at CERN led by MIT physicists has observed clear signs that quarks create wakes as they speed through the plasma, similar to a duck trailing ripples through water. The findings are the first direct evidence that quark-gluon plasma reacts to speeding particles as a single fluid, sloshing and splashing in response, rather than scattering randomly like individual particles.
Charge density waves (CDWs) are ordered, crystal-like patterns in the arrangement of electrons that spontaneously form inside some solid materials. These patterns can change how electricity flows through materials, in some cases prompting the emergence of superconductivity or other unusual physical states.
Physics theories suggest that at certain temperatures CDWs “melt,” similarly to how conventional solids transition to a liquid state. So far, however, this transition to a liquid CDW had not yet been observed experimentally.
Researchers at University of California Los Angeles (UCLA) have gathered the first direct evidence of a CDW liquid state in the layered transition metal dichalcogenide 1T-TaS2. Their paper, published in Nature Physics, could open new possibilities for the study of hidden electronic phases in correlated physical systems.
Researchers at the University of Basel and the ETH in Zurich have succeeded in changing the polarity of a special ferromagnet using a laser beam. In the future, this method could be used to create adaptable electronic circuits with light.
In a ferromagnet, combined forces are at work. In order for a compass needle to point north or a fridge magnet to stick to the fridge door, countless electrons spin inside them, each of which only creates a tiny magnetic field, all need to line up in the same direction. This happens through interactions between the spins, which have to be stronger than the disordered thermal motion inside the ferromagnet. If the temperature of the material is below a critical value, it becomes ferromagnetic.
Conversely, to change the polarity of a ferromagnet, one usually needs to first heat it up above its critical temperature. The electron spins can then reorient themselves, and after cooling down, the magnetic field of the ferromagnet eventually points in a different direction.
That sense of certainty and predictability has now gone, and not because innovation has stopped, but because the physical assumptions that once underpinned it no longer hold.
So what replaces the old model of automatic speed increases? The answer is not a single breakthrough, but several overlapping strategies.
One involves new materials and transistor designs. Engineers are refining how transistors are built to reduce wasted energy and unwanted electrical leakage. These changes deliver smaller, more incremental improvements than in the past, but they help keep power use under control.
When materials become just one atom thick, melting no longer follows the familiar rules. Instead of jumping straight from solid to liquid, an unusual in-between state emerges, where atomic positions loosen like a liquid but still keep some solid-like order. Scientists at the University of Vienna have now captured this elusive “hexatic” phase in real time by filming an ultra-thin silver iodide crystal as it melted inside a protective graphene sandwich.
Using NASA’s IXPE, astronomers captured an unprecedented view of a white dwarf star actively feeding on material from a companion. The data revealed giant columns of ultra-hot gas shaped by the star’s magnetic field and glowing in intense X-rays. These features are far too small to image directly, but X-ray polarization allowed scientists to map them with surprising precision. The results open new doors for understanding extreme binary star systems.
Scientists have, for the first time, used NASA’s IXPE (Imaging X-ray Polarization Explorer) to investigate a white dwarf star. The mission’s ability to measure the polarization of X-rays allowed astronomers to closely examine EX Hydrae, a type of system known as an intermediate polar. These observations provided new insight into the physical structure and behavior of powerful binary star systems.
During 2024, IXPE spent nearly a full week observing EX Hydrae. This white dwarf system lies about 200 light-years from Earth in the constellation Hydra. The results of the study were published in the Astrophysical Journal. Researchers from the Massachusetts Institute of Technology in Cambridge led the work, with additional contributors from the University of Iowa, East Tennessee State University, the University of Liége, and Embry Riddle Aeronautical University.