Lifeboat Foundation

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Hydrides are created by combining rare earth metals with hydrogen, then adding nitrogen or carbon. In recent years, they offered scientists a tantalizing “working recipe” for creating superconducting materials.

Technically speaking, rare earth metal hydrides take the form of cage-like structures called clathrates, where the rare earth metal ions serve as carrier donors and supply enough electrons to promote the dissociation of the H2 molecules. Carbon and nitrogen aid in material stabilization. The bottom line is that superconductivity can occur at lower pressures.

Continue reading “Scientists created a superconducting material at both a temperature and pressure” »

Processing more data in more places while minimizing its movement becomes a requirement and a challenge.

Movement and management of data inside and outside of chips is becoming a central theme for a growing number of electronic systems, and a huge challenge for all of them.

Entirely new architectures and techniques are being developed to reduce the movement of data and to accomplish more per compute cycle, and to speed the transfer of data between various components on a chip and between chips in a package. Alongside of that, new materials are being developed to increase electron mobility and to reduce resistance and capacitance.

A new mechanism that gives rise to superconductivity in a material where the speed of electrons is almost zero has been discovered by scientists at The University of Texas at Dallas and their partners at The Ohio State University. This breakthrough could pave the way for the development of novel superconductors.

The results of their study, which was recently published in the journal Nature, describe a novel approach to calculate electron speed. This study also represents the first instance where quantum geometry has been recognized as the primary contributing mechanism to superconductivity in any material.

The material the researchers studied is twisted bilayer graphene.

Was divided, one half jointly to Leo Esaki and Ivar Giaever ‘for their experimental discoveries regarding tunneling phenomena in semiconductors and superconductors, respectively’ and the other half to Brian David Josephson ‘for his theoretical predictions of the properties of a supercurrent through a tunnel barrier, in particular those phenomena which are generally known as the Josephson effects’

“Measuring tBLG devices: the cryostat insert used in the experiments. (Courtesy: J Lau)” Measuring tB.

The breakthrough could one day transform technologies that use electric energy, but it comes from a team facing doubts after a retracted paper on superconductors.

Another part of that wariness arises because, to date, no one has independently reproduced Dias’ team’s results. This lack of verification was raised by Jorge Hirsch of the University of California, San Diego, in the last talk of the session in which Dias and his team spoke. Hirsch argued that those claiming to have created high-temperature superconducting hydrides suffered from “confirmation bias,” cherry-picking evidence to support their agenda. (Hirsch has been an outspoken critic of Dias’ work.) As the last question of the session, Dias asked Hirsch, “Could you also have confirmation bias?” “Maybe,” Hirsch replied.

After the session, a few attending researchers—all collaborators of Dias—spoke with Physics Magazine, telling us that they disagreed with Hirsch’s cherry-picking conclusion. One of them, Russell Hemley of the University of Illinois Chicago confirmed Pasan’s claim that they have replicated the 2020 carbonaceous sulfur hydride—as reported in an arXiv paper that the team recently posted [3].

Dias’ group still needs to more precisely characterize NLH’s chemical composition, Pasan said. The samples also appear to consist of two phases, an observation that they need to investigate. Ultimately, they plan to innovate upon this material to create a superconductor at ambient pressure and temperature conditions, a goal that Pasan said he thinks is feasible. But extraordinary claims require extraordinary evidence, and the community has much of the latter still to gather.

The ultimate miniature electronic device may be one that manipulates individual electrons with subnanometer and subfemtosecond precision. The past few decades have seen immense progress in the control of ultrafast electronic processes, including in the context of vacuum nanoelectronics, where electrons travel from a nanoscale emitter to a target electrode through a vacuum. Now Hirofumi Yanagisawa at the Japan Science and Technology Agency and colleagues have taken an important step toward optimal spatial control by using the orbitals of a single molecule to shape its electron emission (Fig. 1) [1]. The approach offers the prospect of building highly controllable electron emitters, but also of furthering our understanding of the role of molecular orbitals in the electronic structure of solids.

Fundamental to achieving extreme control over electron emission is defining the spot from which electrons are ejected from the emitter. One approach is to physically shape the material of the emitter into the desired spot pattern. Doing that at the subnanometer scale would entail significant material-and fabrication-related challenges, however. Instead, Yanagisawa and colleagues have demonstrated the clever idea of using the inherent electronic structure of a molecule to route the electrons for emission. In essence, the molecular orbitals are used as a spatial filter to control the emission pattern.

The team’s work grows out of two broad areas of investigation that have progressed significantly over the past few decades. One of these involves the study of femto-and attosecond electron dynamics and the creation of ultrafast electron sources, exemplified by the 2006 demonstration of tight spatial control over femtosecond electron pulses through emission from a nanoscale metallic tip [2– 8]. The second is the study of electron emission patterns originating from molecular structures and nanostructures. Examples include patterns corresponding to the tip structures of nanotubes and nanowires, which change as the tip evolves during nanotube growth [9– 11]. It is by combining the techniques of ultrafast emission and emission microscopy that Yanagisawa and colleagues have demonstrated that the emission patterns can be directly linked to specific molecular orbitals.

A group led by Professor Ralf Rabus, a microbiologist at the University of Oldenburg, and his Ph.D. student Patrick Becker has made significant advancements in comprehending the cellular processes of a widespread environmental bacterium. The team conducted an extensive analysis of the entire metabolic network of the bacterial strain Aromatoleum aromaticum EbN1^T and utilized the findings to construct a metabolic model that allows them to forecast the growth of these microbes in various environmental conditions.

According to their report in the journal mSystems, the researchers uncovered surprising mechanisms that enable the bacteria to adjust to fluctuating environmental conditions. These results are crucial for the study of ecosystems, where the Aromatoleum strain, as a representative of a significant group of environmental bacteria, can act as a model organism. The findings could also have implications for the cleanup of contaminated sites and biotechnological applications.

The studied bacterial strain specializes in the utilization of organic substances that are difficult to break down and is generally found in soil and in aquatic sediments. The microbes thrive in a variety of conditions including oxygen, low-oxygen, and oxygen-free layers, and are also extremely versatile in terms of nutrient intake. They metabolize more than 40 different organic compounds including highly stable, naturally occurring substances such as components of lignin, the main structural material found in wood, and long-lived pollutants and components of petroleum.