Computers Math

Scientists and engineers have been pushing for the past decade to leverage an elusive ferroelectric material called hafnium oxide, or hafnia, to usher in the next generation of computing memory. A team of researchers including the University of Rochester’s Sobhit Singh published a Proceedings of the National Academy of Sciences study outlining progress toward making bulk ferroelectric and antiferroelectric hafnia available for use in a variety of applications.
In a specific crystal phase, hafnia exhibits ferroelectric properties — that is, electric polarization that can be changed in one direction or another by applying an external electric field. This feature can be harnessed in data storage technology. When used in computing, ferroelectric memory has the benefit of non-volatility, meaning it retains its values even when powered off, one of several advantages over most types of memory used today.
“Hafnia is a very exciting material because of its practical applications in computer technology, especially for data storage,” says Singh, an assistant professor in the Department of Mechanical Engineering. “Currently, to store data we use magnetic forms of memory that are slow, require a lot of energy to operate, and are not very efficient. Ferroelectric forms of memory are robust, ultra-fast, cheaper to produce, and more energy-efficient.”
But Singh, who performs theoretical calculations to predict material properties at the quantum level, says that bulk hafnia is not ferroelectric at its ground state. Until recently, scientists could only get hafnia to its metastable ferroelectric state when straining it as a thin, two-dimensional film of nanometer thickness.
In 2021, Singh was part of a team of scientists at Rutgers University that got hafnia to stay at its metastable ferroelectric state by alloying the material with yttrium and rapidly cooling it. Yet this approach had some drawbacks. “It required a lot of yttrium to get to that desired metastable phase,” he says. “So, while we achieved what we were going for, at the same time we were hampering a lot of the material’s key features because we were introducing a lot of impurities and disorder in the crystal. The question became, how can we get to that metastable state with as little yttrium as possible to improve the resulting material’s properties?”
In the new study, Singh calculated that by applying significant pressure, one could stabilize bulk hafnia in its metastable ferroelectric and antiferroelectric forms — both of which are intriguing for practical applications in next-generation data and energy storage technologies. A team led by Professor Janice Musfeldt at the University of Tennessee, Knoxville, carried out the high-pressure experiments and demonstrated that, at the predicted pressure, the material converted into the metastable phase and remained there even when pressure was removed.
“This is as an excellent example of experimental-theoretical collaboration,” says Musfeldt.
The new approach required only about half as much yttrium as a stabilizer, thereby considerably improving the quality and purity of the grown hafnia crystals. Now, Singh says that he and the other scientists will push to use less and less yttrium until they figure out a way for producing ferroelectric hafnia in bulk for widespread use.
And as hafnia continues to draw increasing attention due to its intriguing ferroelectricity, Singh is organizing an invited focus session on the material at the upcoming American Physical Society’s March Meeting 2024. More

Researchers at Linköping University, Sweden, have developed a new, more environmentally friendly way to create conductive inks for use in organic electronics such as solar cells, artificial neurons, and soft sensors. The findings, published in the journal Nature Communications, pave the way for future sustainable technology.
Organic electronics are on the rise as a complement and, in some cases, a replacement to traditional silicon-based electronics. Thanks to simple manufacturing, high flexibility, and low weight combined with the electrical properties typically associated with traditional semiconductors, it can be useful for applications such as digital displays, energy storage, solar cells, sensors, and soft implants.
Organic electronics are built from semiconducting plastics, known as conjugated polymers. However, processing conjugated polymers often requires environmentally hazardous, toxic, and flammable solvents. This is a major obstacle to the wide commercial and sustainable use of organic electronics.
Now, researchers at Linköping University have developed a new sustainable method for processing these polymers from water. In addition to being more sustainable, the new inks are also highly conductive.
“Our research introduces a new approach to processing conjugated polymers using benign solvents such as water. With this method, called ground-state electron transfer, we not only get around the problem of using hazardous chemicals, but we can also demonstrate improvements in material properties and device performance,” says Simone Fabiano, senior associate professor at the Laboratory of Organic Electronics.
When researchers tested the new conductive ink as a transport layer in organic solar cells, they found that both stability and efficiency were higher than with traditional materials. They also tested the ink to create electrochemical transistors and artificial neurons, demonstrating operating frequencies similar to biological neurons.
“I believe that these results can have a transformative impact on the field of organic electronics. By enabling the processing of organic semiconductors from green and sustainable solvents like water, we can mass-produce electronic devices with minimal impact on the environment,” says Simone Fabiano, a Wallenberg Academy Fellow. More

A research team led by Lawrence Berkeley National Laboratory (Berkeley Lab) has developed “supramolecular ink,” a new technology for use in OLED (organic light-emitting diode) displays or other electronic devices. Made of inexpensive, Earth-abundant elements instead of costly scarce metals, supramolecular ink could enable more affordable and environmentally sustainable flat-panel screens and electronic devices.
“By replacing precious metals with Earth-abundant materials, our supramolecular ink technology could be a game changer for the OLED display industry,” said principal investigator Peidong Yang, a faculty senior scientist in Berkeley Lab’s Materials Sciences Division and professor of chemistry and materials science and engineering at UC Berkeley. “What’s even more exciting is that the technology could also extend its reach to organic printable films for the fabrication of wearable devices as well as luminescent art and sculpture,” he added.
If you have a relatively new smartphone or flat panel TV, there’s a good chance it features an OLED screen. OLEDs are rapidly expanding in the display market because they are lighter, thinner, use less energy, and have better picture quality than other flat-panel technologies. That’s because OLEDs contain tiny organic molecules that emit light directly, eliminating the need for the extra backlight layer that is found in a liquid crystal display (LCD). However, OLEDs can include rare, expensive metals like iridium.
But with the new material — which the Berkeley Lab team recently described in a new study published in the journal Science — electronics display manufacturers could potentially adopt a cheaper fabrication process that also requires far less energy than conventional methods.
The new material consists of powders containing hafnium (Hf) and zirconium (Zr) that can be mixed in solution at low temperatures — from room temperature up to around 176 degrees Fahrenheit (80 degrees Celsius) — to form a semiconductor “ink.”
Tiny molecular “building block” structures within the ink self-assemble in solution — a process that the researchers call supramolecular assembly. “Our approach can be compared to building with LEGO blocks,” said Cheng Zhu, the co-first author on the paper and a Ph.D. candidate in materials science and engineering at UC Berkeley. These supramolecular structures enable the material to achieve stable and high-purity synthesis at low temperatures, explained Zhu. He developed the material while working as a research affiliate in Berkeley Lab’s Materials Sciences Division and graduate student researcher in the Peidong Yang group at Berkeley Lab and UC Berkeley.
Spectroscopy experiments at UC Berkeley revealed that the supramolecular ink composites are highly efficient emitters of blue and green light — two signifiers of the material’s potential application as an energy-efficient OLED emitter in electronic displays and 3D printing.

Subsequent optical experiments revealed that the blue- and green-emitting supramolecular ink compounds exhibit what scientists call near-unity quantum efficiency. “This demonstrates their exceptional ability to convert nearly all absorbed light into visible light during the emission process,” Zhu explained.
To demonstrate the material’s color tunability and luminescence as an OLED emitter, the researchers fabricated a thin-film display prototype from the composite ink. In an exciting result, they found that the material is suitable for programmable electronic displays.
“The alphabet movie serves as a compelling example that illustrates the application of emissive thin films like supramolecular ink in the creation of fast-switching displays,” said Zhu.
Additional experiments at UC Berkeley showed that the supramolecular ink is also compatible with 3D printing technologies such as for the design of decorative OLED lighting.
Zhu added that manufacturers could also use the supramolecular ink to fabricate wearable devices or high-tech clothing that illuminates for safety in low-light conditions, or wearable devices that display information through the supramolecular light-emitting structures.
The supramolecular ink is another demonstration from the Peidong Yang lab of new sustainable materials that could enable cost-effective and energy-efficient semiconductor manufacturing. Last year, Yang and his team reported a new “multielement ink” — the first “high-entropy” semiconductor that can be processed at low temperature or room temperature.

With their demonstrated stability and shelf life, the supramolecular ink compounds could also help in the commercial advancement of ionic halide perovskites, a thin-film solar material that the display industry has been eyeing for decades. With their low-temperature synthesis in solution, ionic halide perovskites could potentially enable cheaper manufacturing processes for the manufacturing of displays. But high-performance halide perovskites contain the element lead, which is concerning for the environment and public health. In contrast, the new supramolecular ink — which belongs to the ionic halide perovskite family — offers a lead-free formulation without compromising performance.
Now that they have successfully demonstrated the supramolecular ink’s potential in OLED thin films and 3D-printable electronics, the researchers are now exploring the material’s electroluminescent potential. “This involves a focused and specialized investigation into how well our materials can emit light using electrical excitation,” Zhu said. “This step is essential to understanding our material’s full potential for creating efficient light-emitting devices.”
Other authors on the study include Jianbo Jin (co-first author), Zhen Wang, Zhenpeng Xu, Maria C. Folgueras, Yuxin Jiang, Can B. Uzundal, Han K.D. Le, Feng Wang, and Xiaoyu (Rayne) Zheng.
This work was supported by the Department of Energy’s Office of Science. More

Computer science researchers have developed a new way to identify security weaknesses that leave people vulnerable to account takeover attacks, where a hacker gains unauthorized access to online accounts.
Most mobiles are now home to a complex ecosystem of interconnected operating software and Apps, and as the connections between online services has increased, so have the possibilities for hackers to exploit the security weaknesses, often with disastrous consequences for their owner.
Dr Luca Arnaboldi, from the University of Birmingham’s School of Computer Science, explains: “The ruse of looking over someone’s shoulder to find out their PIN is well known. However, the end game for the attacker is to gain access to the Apps, which store a wealth of personal information and can provide access to accounts such as Amazon, Google, X, Apple Pay, and even bank accounts.”
To understand and prevent these attacks, researchers had to get into the mind of the hacker, who can build a complex attack by combining smaller tactical steps.
Dr Luca Arnaboldi worked with Professor David Aspinall from the University of Edinburgh, Dr Christina Kolb from the University of Twente, and Dr Sasa Radomirovic from the University of Surrey to define a way of cataloguing security vulnerabilities and modelling account takeover attacks, by reducing them their constituent building blocks.
Until now, security vulnerabilities have been studied using ‘account access graphs’, which shows the phone, the SIM card, the Apps, and the security features that limit each stage of access.
However, account access graphs do not model account takeovers, where an attacker disconnects a device, or an App, from the account ecosystem by, for instance, by taking out the SIM card and putting it into a second phone. As SMS messages will be visible on the second phone, the attacker can then use SMS-driven password recovery methods.

The researchers overcame this obstacle by developing a new way to model how account access changes as devices, SIM cards, or Apps are disconnected from the account ecosystem.
Their method, which is based on the formal logic used by mathematicians and philosophers, captures the choices faced by a hacker who has access to the mobile phone and the PIN.
The researchers expect this approach, which is published in the Proceedings of the 28th European Symposium on Research in Computer Security (ESORICS 23), to be adopted device manufacturers and App developers who wish to catalogue vulnerabilities, and further their understanding of complex hacking attacks.
The published account also details how the researchers tested their approach against claims made in a report by Wall Street Journal, which speculated that an attack strategy used to access data and bank accounts on an iPhone could be replicated on Android, even though no such attacks were reported.
Apps for Android are installed from the Play Store, and installation requires a Google account, and the researchers found that this connection provides some protection against attacks. Their work also suggested a security fix for iPhone.
Dr Arnaboldi said: “The results of our simulations showed the attack strategies used by iPhone hackers to access Apple Pay could not be used to access Android Pay on Android, due to security features on the Google account. The simulations also suggested a security fix for iPhone — requiring the use of a previous password as well as a pin, a simple choice that most users would welcome.”
Apple has now implemented a fix for this, providing a new layer of protection for iPhone users1.

The researchers repeated this exercise across other devices (Motorola G10 Android 11, Lenovo YT-X705F Android 10, Xiaomi Redmi Note Pro 10 Android 11, and Samsung Galaxy Tab S6 Lite Android). Here they found that the devices that had their own manufacturer accounts (Samsung and Xiaomi) had the same vulnerability as Apple — although the Google account remained safe, the bespoke accounts were compromised.
The researchers also used their method to test the security on their own mobile devices, with an unexpected result. One of them found that giving his wife access to a shared iCloud account had compromised his security — while his security measures were as secure as they could be, her chain of connections was not secure.
Dr Arnaboldi is currently engaged in Academic Consultancy where he works with major corporates and internet-based companies to improve their defences against hacking. More

Scientists have created the world’s first working nanoscale electromotor, according to research published in the journal Nature Nanotechnology. The science team designed a turbine engineered from DNA that is powered by hydrodynamic flow inside a nanopore, a nanometer-sized hole in a membrane of solid-state silicon nitride.
The tiny motor could help spark research into future applications such as building molecular factories for useful chemicals or medical probes of molecules inside the bloodstream to detect diseases such as cancer.
“Common macroscopic machines become inefficient at the nanoscale,” said study co-author professor Aleksei Aksimentiev, a professor of physics at the University of Illinois at Urbana-Champagne. “We have to develop new principles and physical mechanisms to realize electromotors at the very, very small scales.”
The experimental work on the tiny motor was conducted by Cees Dekker of the Delft University of Technology and Hendrik Dietz of the Technical University of Munich.
Dietz is a world expert in DNA origami. His lab manipulated DNA molecules to make the tiny motor’s turbine, which consisted of 30 double-stranded DNA helices engineered into an axle and three blades of about 72 base pair length. Decker’s lab work demonstrated that the turbine can indeed rotate by applying an electric field. Aksimentiev’s lab carried out all-atom molecular dynamics simulations on a system of five million atoms to characterize the physical phenomena of how the motor works.
The system was the smallest representation that could yield meaningful results about the experiment; however, “it was one of the largest ever simulated from the DNA origami perspective,” Aksimentiev said.
Mission Impossible to Mission Possible
The Texas Advanced Computing Center (TACC) awarded Aksimentiev a Leadership Resource Allocation to aid his study of mesoscale biological systems on the National Science Foundation (NSF)-funded Frontera, the top academic supercomputer in the U.S.

“Frontera was instrumental in this DNA nanoturbine work,” Aksimentiev said. “We obtained microsecond simulation trajectories in two to three weeks instead of waiting for a year or more on smaller computing systems. The big simulations were done on Frontera using about a quarter of the machine — over 2,000 nodes,” Aksimentiev said. “However, it’s not just the hardware, but also the interaction with TACC staff. It’s extremely important to make the best use of the resources once we have the opportunity.”
Aksimentiev was also awarded supercomputer allocations for this work by the NSF-funded Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support (ACCESS) on Expanse of the San Diego Supercomputer Center and Anvil of Purdue University.
“We had up to 100 different nanomotor systems to simulate. We had to run them for different conditions and in a speedy manner, which the ACCESS supercomputers assisted with perfectly,” Aksimentiev said. “Many thanks to the NSF for their support — we would not be able to do the science that we do without these systems.”
DNA as a Building Block
The success with the working DNA nanoturbine builds on a previous study that also used Frontera and ACCESS supercomputers. The study showed that a single DNA helix is the tiniest electromotor that one can build — it can rotate up to a billion revolutions per minute.
DNA has emerged as a building material at the nanoscale, according to Aksimentiev.

“The way DNA base pair is a very powerful programming tool. We can program geometrical, three-dimensional objects from DNA using the Cadnano software just by programming the sequence of letters that make up the rungs of the double helix,” he explained.
Another reason for using DNA as the building block is that it carries a negative charge, an essential characteristic to make the electromotor.
“We wanted to reproduce one of the most spectacular biological machines — ATP synthase, which is driven by electric field. We chose to do our motor with DNA,” Aksimentiev said.
“This new work is the first nanoscale motor where we can control the rotational speed and direction,” he added. It’s done by adjusting the electric field across the solid state nanopore membrane and the salt concentrations of the fluid that surrounds the rotor.
“In the future, we might be able to synthetize a molecule using the new nanoscale electromotor, or we can use it to as an element of a bigger molecular factory, where things are moved around. Or we could imagine it as a vehicle for soft propulsion, where synthetic systems can go into a blood stream and probe molecules or cells one at a time,” Aksimentiev said.
If you think this sounds like something out of a 1960’s sci-fi movie, you are right. In the movie Fantastic Voyage, a team of Americans in a nuclear submarine is shrunk and injected into a scientist’s body to fix a blood clot and need to work quickly before the miniaturization wears off.
As far-fetched as this might sound, Aksimentiev says that the concept and the elements of the machines we are developing today could enable something like this to happen.
“We were able to accomplish this because of supercomputers,” Aksimentiev said. “Supercomputers are becoming more and more indispensable as the complexity of the systems that we build increases. They’re the computational microscopes, which at ultimate resolutions can see the motion of individual atoms and how that is coupled to a bigger system.”
Funding came from ERC Advanced Grant no. 883684 and the NanoFront and BaSyC programmes; ERC Consolidator Grant to H.D. (GA no. 724261), the Deutsche Forschungsgemeinschaft via the Gottfried-Wilhelm-Leibniz Programme (to H.D.) and the SFB863 Project ID 111166240 TPA9; National Science Foundation grant DMR-1827346; the Max Planck School Matter to Life and the MaxSynBio Consortium. Supercomputer time was provided through TACC Leadership Resource Allocation MCB20012 on Frontera and through ACCESS allocation MCA05S028. More

The researchers headed by Dr. Phillip Ozimek from the Faculty of Psychology at Ruhr University Bochum, Germany, recruited 1,230 people for their online survey. In order to participate, respondents had to use at least one social media channel at least once a week. On average, the participants stated that they spent just over two hours a day on social media.
The research team used six different questionnaires to determine the extent to which the participants had a materialistic attitude and tended to compare themselves with others, whether they used social media more actively or passively, whether they were addicted to social media, how stressed and how satisfied they were with their lives.
Downward spiral set in motion
“The data showed that a stronger materialistic approach goes hand in hand with a tendency to compare oneself with others,” points out Phillip Ozimek. This comparison is very easy to make on social media, primarily through passive use, i.e. by looking at the content posted by other users. Materialism and passive use were also linked to addictive use of social media. “By this we mean, for example, that users are constantly thinking about the respective channels and fear that they are missing out on something if they are not online,” explains Phillip Ozimek. This in turn leads to symptoms of poorer mental health, i.e. stress. The final link in the chain is reduced life satisfaction. “Social media is one of six stepping stones to unhappiness,” concludes Phillip Ozimek.
Social media attracts and breeds materialists
“Overall, the study provides further evidence that the use of social media is associated with risks, especially for people with a highly materialistic mindset,” says the psychologist. This is particularly worrying, because social media can trigger and increase materialistic values, for example through (influencer) marketing. At the same time, the platforms attract materialists anyway, as they are a perfect way to satisfy many materialistic needs.
“It’s definitely a good idea to be aware of the amount of time you spend on social media and to reduce it,” recommends Phillip Ozimek. He advises against giving up Social Media completely. “If you did, you’re likely to overcompensate.” The research team also suggests recording materialism and social media use in patients undergoing treatment for mental health disorders. “While these factors are often irrelevant, they can be a starting point for additional interventions that patients can try out at home.” More

Artificial intelligence has become the Swiss Army knife of the business world, a universal tool for increasing sales, optimizing efficiency, and interacting with customers. But new research from Texas McCombs explores another purpose for AI in business: to contribute to the social good.
It can do so by helping businesses better serve vulnerable consumers: anyone in the marketplace who experiences limited access to and control of resources.
“AI is widely recognized for its operational and financial benefits, but it also holds promise for harnessing social good and helping businesses adopt socially responsible practices,” says co-author Gizem Yalcin Williams, Texas McCombs assistant professor of marketing.
With Erik Hermann of ESCP Business School in Berlin and Stefano Puntoni of the University of Pennsylvania’s Wharton School, Williams devised an AI framework that businesses can use to identify vulnerable consumers, address their specific needs, and mitigate potential discrimination and inequalities.
By making customer service more accessible, more interactive, and more dynamic, Williams says, AI can help vulnerable consumers improve their understanding of specific information so that they can make better decisions for themselves. For example, there are already AI tools businesses can use to analyze consumer voice and reactions, while providing real-time feedback to customer service representatives, along with tips to improve the interaction. Key concepts of the framework include:
We’re All Vulnerable (Sometimes). Rather than always being an ongoing condition, vulnerability may be a dynamic state that can come and go. Cognitive and physical limitations can compromise a person’s judgment, but so can emotional distress, such as suffering a layoff, breakup, or death in the family.
“Vulnerability can differ in duration and intensity, but literally every consumer can be vulnerable,” Williams says.

This revised definition of vulnerability opens new doors for AI technologies to do social good, she adds. “With advancements in machine learning and natural language processing algorithms, AI is uniquely positioned to identify vulnerable consumers and to help employees better serve and empower these customers.”
Rating Risk. Recent reports indicate that customer service agents are often unaware when they interact with vulnerable consumers. But AI can perform real-time analysis of consumer chat responses and use cues to build a risk score for agents.
Targeting Extra Support. When AI detects vulnerability, it can offer customer service agents customized tips and suggest special measures. For example, if a consumer shows signs of being overwhelmed or having trouble processing information, AI can recommend that agents explain options in simple terms, along with their pros and cons.
Positive Ripple Effects. Designing and integrating AI into customer service requires investment. But by detecting vulnerability and guiding consumers through vulnerable times, businesses can harvest bothfinancial and reputational benefits.
“Doing good often pays off,” Williams says. “When effectively implemented, businesses utilizing AI to empower their vulnerable customers can expect a positive spillover, fostering increased loyalty, improved customer satisfaction, and boosted profits.”
“Deploying Artificial Intelligence in Services to AID Vulnerable Consumers” is published in the Journal of the Academy of Marketing Science. More

The quantum ground state of an acoustic wave of a certain frequency can be reached by completely cooling the system. In this way, the number of quantum particles, the so-called acoustic phonons, which cause disturbance to quantum measurements, can be reduced to almost zero and the gap between classical and quantum mechanics bridged.
Over the past decade, major technological advances have been made, making it possible to put a wide variety of systems into this state. Mechanical vibrations oscillating between two mirrors in a resonator can be cooled to very low temperatures as far as the quantum ground state. This has not yet been possible for optical fibers in which high-frequency sound waves can propagate. Now researchers from the Stiller Research Group have taken a step closer to this goal.
In their study, recently published in Physical Review Letters, they report that they were able to lower the temperature of a sound wave in an optical fiber initially at room temperature by 219 K using laser cooling, ten times further than had previously been reported. Ultimately, the initial phonon number was reduced by 75%, at a temperature of 74 K, -194 Celsius. Such a drastic reduction in temperature was made possible by the use of laser light. Cooling of the propagating sound waves was achieved via the nonlinear optical effect of stimulated Brillouin scattering, in which light waves are efficiently coupled to sound waves. Through this effect, the laser light cools the acoustic vibrations and creates an environment with less thermal noise which is, to an extent, “disturbing” noise for a quantum communication system, for example. “An interesting advantage of glass fibers, in addition to this strong interaction, is the fact that they can conduct light and sound excellently over long distances,” says Laura Blázquez Martínez, one of the lead authors of the article and a doctoral student in the Stiller research group.
Most physical platforms previously brought to the quantum ground state were microscopic. However, in this experiment, the length of the optical fiber was 50 cm and a sound wave extending over the full 50 cm of the core of the fiber was cooled to extremely low temperatures. “These results are a very exciting step towards the quantum ground state in waveguides and the manipulation of such long acoustic phonons opens up possibilities for broadband applications in quantum technology,” according to Dr. Birgit Stiller, head of the quantum optoacoustics group.
Sound, in the day-to-day classical world, can be understood as a density wave in a medium. However, from the perspective of quantum mechanics, sound can also be described as a particle: the phonon. This particle, the sound quantum, represents the smallest amount of energy which occurs as an acoustic wave at a certain frequency. In order to see and study single quanta of sound, the number of phonons must be minimized. The transition from the classical to quantum behavior of sound is often more easily observed in the quantum ground state, where the number of phonons is close to zero on average, such that the vibrations are almost frozen and quantum effects can be measured. Stiller: “This opens the door to a new landscape of experiments that allow us to gain deeper insights into the fundamental nature of matter.” The advantage of using a waveguide system is that light and sound are not bound between two mirrors, but propagating along the waveguide. The acoustic waves exist as a continuum — not only for certain frequencies — and can have a broad bandwidth, making them promising for applications such as high-speed communication systems.
“We are very enthusiastic about the new insights that pushing these fibers into the quantum ground state will bring,” emphasizes the research group leader. “Not only from the fundamental research point of view, allowing us to peek into the quantum nature of extended objects, but also because of the applications this could have in quantum communications schemes and future quantum technologies.” More