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Category: particle physics – Page 2

Pressure turns Ångström-thin semiconducting bismuth into a metal, expanding options for reconfigurable electronics

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.

Bacterial motility helps uncover how self-propelled particles distribute in active matter systems

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.

Old tires find new life: Rubber particles strengthen superhydrophobic coatings against corrosion

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.

Predictive rule reveals which sulfur-based building blocks create sustainable, degradable plastics

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 . 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.

Simulations hint at new strongly correlated states of matter in ultracold polar molecules

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.

The search for neutrinoless double beta decay gets some noise cancelling headphones

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 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.

With a new molecule-based method, physicists peer inside an atom’s nucleus

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 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 .

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.

Novel carbon nanotube-based transistors reach THz frequencies

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 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 applied to a gate electrode.

Notably, when arrays of CNTs are used to develop MOSFETs, they can operate at (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.

Nuclear power in your pocket? 50-year battery innovation

While the technology of nuclear batteries has been available since the 1950s, today’s drive to electrify and decarbonize increases the impetus to find emission-free power sources and reliable energy storage. As a result, innovations are bringing renewed focus to nuclear energy in batteries.

Nuclear batteries — those using the natural decay of radioactive material to create an electric current — have been used in space applications or remote operations such as arctic lighthouses, where changing a battery is difficult or even impossible. The Mars Science Laboratory rover, for example, uses radioisotopic power systems (RPS), which convert heat from radioactive decay into electricity via a thermoelectric generator. Betavolt’s innovation, 3, is a betavoltaic battery that uses beta particles rather than heat as its energy source. (Probably a repost from March 11 2024)

There are additional challenges that hinder the wider usage of these and all types of nuclear batteries, particularly material supply and discomfort with the use of radioactive materials. Yet, the physical and materials science behind this technology could unlock important advances for CO2-free energy and provide power for applications where currently available energy storage technologies are insufficient.

How do betavoltaic batteries work?

Betavoltaic batteries contain radioactive emitters and semiconductor absorbers. As the emitter material naturally decays, it releases beta particles, or high-speed electrons, which strike the absorber material in the battery, separating electrons from atomic nuclei in the semiconductor absorber. Separation of the resulting electron-hole pairs generates an electric current in the absorber, resulting in electrical power that can be delivered by the battery.

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