How did the universe come into being? There are a multitude of theories on this subject. In a Physical Review Letters paper, three scientists formulate a new model: according to this, inflation, the first, very rapid expansion of the universe, would have taken place in a warm environment consisting of known elementary particles.
Two-dimensional (2D) materials, sparked by the isolation of Nobel-prize-winning graphene in 2004, has revolutionized modern materials science by showing that electrical, optical, and mechanical behaviors can be tuned simply by adjusting the thickness, strain, or stacking order of such 2D materials. From transistors and flexible display to neuromorphic chips, the future of electronics is expected to be significantly empowered by 2D materials.
In a new study published in Nano Letters titled “Pressure-Driven Metallicity in Ångström-Thickness 2D Bismuth and Layer-Selective Ohmic Contact to MoS2,” researchers led by SUTD have discovered that a gentle squeeze is enough to make bismuth—one of the heaviest elements in the periodic table—switch its electrical personality.
Using state-of-the-art density functional theory (DFT) simulations, the team showed that when a single layer of bismuth, only a few atoms thick, is compressed or “squeezed” between surrounding materials, the atoms reorganize from a slightly corrugated (or buckled) structure into a perfectly flat one. This structural flattening, though subtle, has dramatic electronic consequences: it eliminates the energy band gap and allows electrons to move freely, turning the material metallic.
A collaborative team of physicists and microbiologists from UNIST and Stanford University has, for the first time, uncovered the fundamental laws governing the distribution of self-propelled particles, such as bacteria.
Published in Physical Review Letters, this breakthrough has been jointly led by Professor Joonwoo Jeong in the UNIST Department of Physics, Professor Robert J. Mitchell in the UNIST Department of Biological Sciences, and Professor Sho C. Takatori at Stanford University.
The study reveals that the distribution of living bacteria is governed by a delicate balance between their motility and their affinity for specific liquid environments. Interestingly, the findings highlight a phenomenon consistent with the like-attracts-like principle.
Superhydrophobic materials offer a strategy for developing marine anti-corrosion materials due to their low solid-liquid contact area and low surface energy. However, existing superhydrophobic anti-corrosion materials often suffer from poor mechanical stability and inadequate long-term protection, limiting their practical application in real-world environments.
Plastics pose a significant waste problem: many conventional plastics do not degrade, or do so only with great difficulty. This makes research into new plastics essential—materials that retain useful properties but can also be deliberately broken down or recycled. Such innovations could lead to more sustainable materials, enabling the use of plastics in a way that conserves resources over the long term.
According to a study published in the journal Angewandte Chemie International Edition, incorporating sulfur atoms into polymer chains makes them more degradable.
Sulfur atoms enhance the sustainability of polymers because the bonds between carbon and sulfur atoms are easier to break than the bonds between carbon and other carbon or oxygen atoms. This allows sulfur-containing plastics to degrade under relatively mild conditions. However, strategies for synthesizing these plastics are still underdeveloped, which hinders large-scale production.
Bose-Einstein condensates (BECs) are fascinating states of matter that emerge when atoms or molecules are cooled to extremely low temperatures just slightly above absolute zero (0 K). In 2023, physicists at Columbia University realized BECs comprised of ultracold molecules for the very first time.
Building on their work, another research group at TU Wien and the Vienna Center for Quantum Science and Technology recently set out to investigate the behavior of these ultracold dipolar molecules, while also exploring the possibility that they could spontaneously organize themselves into new forms of matter. Their findings, published in Physical Review Letters, suggest that new correlated states could emerge in ultracold polar molecules, showing that these states could be probed in future experiments.
“BECs of ultracold polar molecules were a decade-long goal, but have only been realized experimentally very recently,” Matteo Ciardi, co-author of the paper, told Phys.org.
Deep under a mountain in Italy, researchers continue to push the boundaries of science with an experiment that could rewrite the Standard Model of Particle Physics.
Their experiment, known as the Cryogenic Underground Observatory for Rare Events (CUORE), which includes researchers from Yale, has now collected two ton-years of data (the equivalent of collecting data for two years if the cube-shaped crystals in the CUORE detector weighed one ton) in a years-long effort to document a theory of rare nuclear particle decay called neutrinoless double beta decay.
Standard double beta decay is already a proven particle process. When it occurs, two neutrons, which are uncharged particles in the nucleus of an atom, transform into two protons and emit two electrons and two antineutrinos. Antineutrinos are the antimatter counterpart to neutrinos.
Physicists at MIT have developed a new way to probe inside an atom’s nucleus, using the atom’s own electrons as “messengers” within a molecule.
In a study appearing today in the journal Science, the physicists precisely measured the energy of electrons whizzing around a radium atom that had been paired with a fluoride atom to make a molecule of radium monofluoride. They used the environments within molecules as a sort of microscopic particle collider, which contained the radium atom’s electrons and encouraged them to briefly penetrate the atom’s nucleus.
Typically, experiments to probe the inside of atomic nuclei involve massive, kilometers-long facilities that accelerate beams of electrons to speeds fast enough to collide with and break apart nuclei. The team’s new molecule-based method offers a tabletop alternative to directly probe the inside of an atom’s nucleus.
Carbon nanotubes (CNTs), cylindrical nanostructures made of carbon atoms arranged in a hexagonal lattice, have proved to be promising for the fabrication of various electronic devices. In fact, these structures exhibit outstanding electrical conductivity and mechanical strength, both of which are highly favorable for the development of transistors (i.e., the devices that control the flow of current in electronics).
In recent years, several electronics engineers have started using CNTs to develop various electronics, including metal-oxide-semiconductor field-effect transistors (MOSFETs). MOSFETs are transistors that control the flow of current through a semiconducting channel utilizing an electric field applied to a gate electrode.
Notably, when arrays of CNTs are used to develop MOSFETs, they can operate at radio frequencies (RF), the range of electromagnetic waves that support wireless communication. The resulting MOSFETs could thus be particularly advantageous for the advancement of wireless communication systems and technologies.