Designing efficient neuromorphic systems based on nanowire networks remains a challenge. Here, Zhu et al. demonstrate brain-inspired learning and memory of spatiotemporal features using nanowire networks capable of MNIST handwritten digit classification and a novel sequence memory task performed in an online manner.
Connectomics, the ambitious field of study that seeks to map the intricate network of animal brains, is undergoing a growth spurt. Within the span of a decade, it has journeyed from its nascent stages to a discipline that is poised to (hopefully) unlock the enigmas of cognition and the physical underpinning of neuropathologies such as in Alzheimer’s disease.
At its forefront is the use of powerful electron microscopes, which researchers from the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL) and the Samuel and Lichtman Labs of Harvard University bestowed with the analytical prowess of machine learning. Unlike traditional electron microscopy, the integrated AI serves as a “brain” that learns a specimen while acquiring the images, and intelligently focuses on the relevant pixels at nanoscale resolution similar to how animals inspect their worlds.
“SmartEM” assists connectomics in quickly examining and reconstructing the brain’s complex network of synapses and neurons with nanometer precision. Unlike traditional electron microscopy, its integrated AI opens new doors to understand the brain’s intricate architecture. “SmartEM: machine-learning guided electron microscopy” has been published on the pre-print server bioRxiv.
More sophisticated manipulation of complicated materials and their spin states at short time scales will be needed to create the next generation of spintronic devices. But, a thorough understanding of the fundamental physics underpinning nanoscale spin manipulation is necessary to fully utilize these powers for more energy-efficient nanotechnologies.
The JILA team and colleagues from institutions in Sweden, Greece, and Germany investigated the spin dynamics within a unique substance known as a Heusler compound—a combination of metals that exhibits properties similar to those of a single magnetic material. In their investigation, the scientists used a cobalt, manganese, and gallium combination that acted as an insulator for electrons with downwardly oriented spins and a conductor for those with upwardly aligned spins.
Scientists used extreme ultraviolet high-harmonic generation (EUV HHG) light as a probe to track the re-orientations of the spins inside the compound after exciting it with a femtosecond laser. Tuning the color of the EUV HHG probe light is the key to accurately interpreting the spin re-orientations.
Optical tweezers manipulate tiny things like cells and nanoparticles using lasers. While they might sound like tractor beams from science fiction, the fact is their development garnered scientists a Nobel Prize in 2018.
Scientists have now used supercomputers to make optical tweezers safer to use on living cells with applications to cancer therapy, environmental monitoring, and more.
“We believe our research is one significant step closer towards the industrialization of optical tweezers in biological applications, specifically in both selective cellular surgery and targeted drug delivery,” said Pavana Kollipara, a recent graduate of The University of Texas at Austin.
Two-dimensional (2D) materials, composed of a single or a few layers of atoms, are at the forefront of material science, promising revolutionary advancements in technology. These ultra-thin materials exhibit unique and exotic properties, particularly when their layers are stacked and twisted in specific ways.
This manipulation of layers can significantly alter their electronic characteristics, presenting exciting opportunities for the development of next-generation technologies such as more efficient computers and reliable electricity storage systems.
Understanding the intricate relationship between the atomic structure and electronic properties of these materials, however, poses a significant challenge. Traditional microscopy techniques struggle to capture the complete 3D atomic structure of these layered materials, especially when the layers are oriented differently or composed of light elements.
Magnetic random-access memories (MRAMs) are data storage devices that store digital data within nanomagnets, representing it in binary code (i.e., as “0” or “1”). The magnetization of nanomagnets inside these memory devices can be directed upward or downward.
Over the past decade, electronics engineers have introduced techniques that can switch this direction using in-plane electrical currents. These techniques ultimately enabled the creation of a new class of MRAM devices, referred to as spin-orbit torque (SOT)-MRAMs.
While existing techniques to switch magnetization direction of nanomagnets in SOT-MRAMs have proved effective, many only work if external magnetic fields are aligned with the direction of the electric current. In a recent paper published in Nature Electronics, researchers at the National University of Singapore demonstrated the field-free switching of the perpendicular magnetic anisotropy (PMA) ferromagnet cobalt iron boron (CoFeB) at ambient conditions.
For more than 50 years, the semiconductor industry has been hard at work developing advanced technologies that have led to the amazing increases in computing power and energy efficiency that have improved our lives. A primary way the industry has achieved these remarkable performance gains has been by finding ways to decrease the size of the semiconductor devices in microchips. However, with semiconductor feature sizes now approaching only a few nanometers—just a few hundred atoms—it has become increasingly challenging to sustain continued device miniaturization.
To address the challenges associated with fabricating even smaller microchip components, the semiconductor industry is currently transitioning to a more powerful fabrication method—extreme ultraviolet (EUV) lithography. EUV lithography employs light that is only 13.5 nanometers in wavelength to form tiny circuit patterns in a photoresist, the light-sensitive material integral to the lithography process.
The photoresist is the template for forming the nanoscale circuit patterns in the silicon semiconductor. As EUV lithography begins paving the way for the future, scientists are faced with the hurdle of identifying the most effective resist materials for this new era of nanofabrication.
When you think of empty space, you almost certainly imagine a vacuum in which nothing interesting can ever happen. However, if we zoom in to tiny length scales where quantum effects start to become important, it turns out that what you thought was empty is actually filled at all times with a seething mass of electromagnetic activity, as virtual photons flicker in and out of existence. This unexpected phenomenon is known as the vacuum fluctuation field. However, because these fluctuations of light energy are so small and fleeting in time, it is difficult to find ways for matter to interact with them, especially within a single, integrated device.
In a study published this month in Nano Letters (“Electrical Detection of Ultrastrong Coherent Interaction between Terahertz Fields and Electrons Using Quantum Point Contacts”), researchers from the Institute of Industrial Science, The University of Tokyo succeeded in fabricating a single nanoscale hybrid system for doing exactly this. In their design, a quantum point contact connects a single on-chip split-ring resonator with a two-dimensional electron system.
Quantum Hall edge channels at the quantum point contact. (Image: University of Tokyo)
In 2018, researchers reported that they had managed to get a coral larva to survive freezing and thawing for the first time. The scientists had added gold nanoparticles to their antifreeze to help the corals warm evenly during reheating. However, the thawed larvae were unable to settle and develop into adults. Instead, they kept swimming until they died.
When Narida began her experiments with hood corals in 2021, she included gold in her antifreeze recipe and combined several different antifreeze chemicals to reduce the solution’s toxicity. To thaw the animals quickly and minimize damage, Narida used a high-powered laser designed for welding jewelry. Then, she carefully washed the antifreeze away with seawater, rehydrating the corals. In the end, a whopping 11 percent of larvae in the experiment survived thawing, then settled, and developed into adults.
Leandro Godoy, a coral cryobiologist at the Federal University of Rio Grande do Sul in Brazil, is impressed by how many larvae survived after settling. “It’s a huge step,” he says, considering that, in the wild, only about five percent of corals make it that far.
So-called neuromorphic networks could be a much more efficient way to train and run machine learning algorithms.