International Conference on Condensed Matter Physics
Calculations motivated by the successful prediction of the nickelate phase diagram suggest that palladates might hit the sweet spot for high-temperature superconductivity.
Copper-based (cuprate) superconductors have long held the record for the highest superconducting critical temperature (Tc) at ambient pressure. In 2019, after decades of theoretical and experimental effort, researchers reported a nickel-based (nickelate) analog to cuprate superconductors (see Trend: Entering the Nickel Age of Superconductivity). Since then, others have sought to pinpoint the factors that control superconductivity in such single-orbital-dominated systems. Motoharu Kitatani of the University of Hyogo in Japan and his colleagues now identify some of these factors and suggest that swapping out nickel for palladium could deliver a material that superconducts at even higher temperatures than cuprate superconductors [1]. The study could help guide the ongoing search for novel superconducting materials and establish “palladates” as the new kid on the block.
Kitatani and his colleagues previously had used a standard condensed-matter-physics model, called the single-band Hubbard model, to predict Tc for nickelates and had validated their predictions using measurements in defect-free nickelate films. Now, by simulating this system while varying the electrons’ interaction strength, filling factor, and energy-momentum dispersion, the researchers have tracked the strength of electron–electron pairing that leads to the emergence of superconductivity. This allows them to determine the electronic configuration that optimizes Tc. However, according to their results, neither nickelates nor cuprates come close to these optimized conditions. Instead, the researchers have found that palladates, thanks to somewhat weaker interactions and thus weaker correlations, could more closely approach the optimal “Goldilocks” conditions that maximize Tc. The researchers hope their theoretical results will encourage experimentalists to grow and examine palladates as new candidates for higher-Tc options.
In their theoretical work, Dr. Diddo Diddens from Helmholtz Institute Münster of Forschungszentrum Jülich and Prof. Andreas Heuer from the Helmholtz Institute Münster and the Institute of Physical Chemistry of the University of Münster investigated the central question of the extent to which ions in liquid electrolytes move statistically correlated, i.e. together, in one direction. With this knowledge, the influence of individual factors, such as ion pairs on conductivity, can be better determined. The detailed results of their study have been published in the Journal of Chemical Physics and on the pre-print server arXiv. It is often assumed that two ions with the same charge avoid each other due to mutual repulsion and thus move in opposite directions. Now, the researchers are able to show that two neighboring ions with the same charge move in the same direction. "This counter-intuitive behavior can be explained by the fact that the electrolyte, as a liquid, is incompressible, ...
International Conference on Condensed Matter Physics E=mc2 Albert Einstein proposed the most famous formula in physics in a 1905 paper on Special Relativity titled Does the inertia of an object depend upon its energy content? Essentially, the equation says that mass and energy are intimately related. Atom bombs and nuclear reactors are practical examples of the formula working in one direction, turning matter into energy. But until now there has been no way to do the reverse, turn energy into matter. What makes it particularly hard is that c2 term, the speed of light squared. It accounts for the huge amounts of energy released in nuclear reactions, and the huge amount you’d need to inject to turn energy into matter. Previous experiments have always required a little bit of mass, even if it was only an electron’s worth. But scientists at Imperial College London (including a visiting physicist from Germany's Max Planck Institute for Nuclear Physics) think they’ve figured out how to...
In a paper published today in Nature Communications, researchers from the Paul Drude Institute in Berlin, Germany, and the Instituto Balseiro, Bariloche, Argentina, demonstrated that light emitters with different resonance frequencies can asynchronously self-lock their relative energies by exchanging mechanical energy. This finding paves the way for increased control of light sources and GHz-to-THz interconversion relevant to quantum technology. Oscillators with slightly different resonance frequencies tend to lock their frequency to a common value when they start to interact with one another. This phenomenon was originally observed in a system of two pendula sharing the same support by Christiaan Huygens in the 17th century. Huygens first noticed that it was difficult to make two pendula with the same oscillation frequency—a necessary condition to make precise clocks. If, however, he would hang them on a common support, the clocks would slowly synchronize their motion and, after some...
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