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High-temperature superconductivity is superconductivity in materials with a critical temperature above 77 K, the boiling point of liquid nitrogen. They are only "high-temperature" relative to previously known superconductors, which function at colder temperatures, close to absolute zero. The "high temperatures" are still far below ambient, and therefore require cooling. The first breakthrough of high-temperature superconductor was discovered in 1986 by IBM researchers Georg Bednorz and K. Alex Müller. Although the critical temperature is around 35.1 K, this new type of superconductor was readily modified by Ching-Wu Chu to make the first high-temperature superconductor with critical temperature 93 K. Bednorz and Müller were awarded the Nobel Prize in Physics in 1987 "for their important break-through in the discovery of superconductivity in ceramic materials". Most high-Tc materials are type-II superconductors.
Metallic hydrogen is a phase of hydrogen in which it behaves like an electrical conductor. This phase was predicted in 1935 on theoretical grounds by Eugene Wigner and Hillard Bell Huntington.
A room-temperature superconductor is a hypothetical material capable of displaying superconductivity above 0 °C, operating temperatures which are commonly encountered in everyday settings. As of 2023, the material with the highest accepted superconducting temperature was highly pressurized lanthanum decahydride, whose transition temperature is approximately 250 K (−23 °C) at 200 GPa.
Superconductivity is the phenomenon of certain materials exhibiting zero electrical resistance and the expulsion of magnetic fields below a characteristic temperature. The history of superconductivity began with Dutch physicist Heike Kamerlingh Onnes's discovery of superconductivity in mercury in 1911. Since then, many other superconducting materials have been discovered and the theory of superconductivity has been developed. These subjects remain active areas of study in the field of condensed matter physics.
Ho-Kwang (Dave) Mao is a Chinese-American geologist. He is the director of the Center for High Pressure Science and Technology Advanced Research in Shanghai, China. He was a staff scientist at Geophysical Laboratory of the Carnegie Institution for Science for more than 30 years. Mao is a recognized leading scientist in high pressure geosciences and physical science. There are two minerals named after him, Davemaoite and Maohokite.
Iron-based superconductors (FeSC) are iron-containing chemical compounds whose superconducting properties were discovered in 2006. In 2008, led by recently discovered iron pnictide compounds, they were in the first stages of experimentation and implementation..
Solid hydrogen is the solid state of the element hydrogen, achieved by decreasing the temperature below hydrogen's melting point of 14.01 K. It was collected for the first time by James Dewar in 1899 and published with the title "Sur la solidification de l'hydrogène" in the Annales de Chimie et de Physique, 7th series, vol. 18, Oct. 1899. Solid hydrogen has a density of 0.086 g/cm3 making it one of the lowest-density solids.
Robert Miller Hazen is an American mineralogist and astrobiologist. He is a research scientist at the Carnegie Institution of Washington's Geophysical Laboratory and Clarence Robinson Professor of Earth Science at George Mason University, in the United States. Hazen is the Executive Director of the Deep Carbon Observatory.
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A hydrogen clathrate is a clathrate containing hydrogen in a water lattice. This substance is interesting due to its possible use to store hydrogen in a hydrogen economy. A recent review that accounts the state-of-the-art and future prospects and challenges of hydrogen storage as clathrate hydrates is reported by Veluswamy et al. (2014). Another unusual characteristic is that multiple hydrogen molecules can occur at each cage site in the ice, one of only a very few guest molecule that forms clathrates with this property. The maximum ratio of hydrogen to water is 6 H2 to 17 H2O. It can be formed at 250K in a diamond anvil at a pressure of 300MPa (3000 Bars). It takes about 30 minutes to form, so this method is impractical for rapid manufacture. The percent of weight of hydrogen is 3.77%. The cage compartments are hexakaidecahedral and hold from two to four molecules of hydrogen. At temperatures above 160K the molecules rotate around inside the cage. Below 120K the molecules stop racing around the cage, and below 50K are locked into a fixed position. This was determined with deuterium in a neutron scattering experiment.
Artem R. Oganov is a Russian theoretical crystallographer, mineralogist, chemist, physicist, and materials scientist. He is known mostly for his works on computational materials discovery and crystal structure prediction, studies of matter at extreme conditions, including matter of planetary interiors.
Mikhail Ivanovich Eremets was a Belarusian experimentalist in high pressure physics, chemistry and materials science. He was particularly known for his research on superconductivity, having discovered the highest critical temperature of 250 K (-23 °C) for superconductivity in lanthanum hydride under high pressures. Part of his research contains exotic manifestations of materials such as conductive hydrogen, polymeric nitrogen and transparent sodium.
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Rare-earth barium copper oxide (ReBCO) is a family of chemical compounds known for exhibiting high-temperature superconductivity (HTS). ReBCO superconductors have the potential to sustain stronger magnetic fields than other superconductor materials. Due to their high critical temperature and critical magnetic field, this class of materials are proposed for use in technical applications where conventional low-temperature superconductors do not suffice. This includes magnetic confinement fusion reactors such as the ARC reactor, allowing a more compact and potentially more economical construction, and superconducting magnets to use in future particle accelerators to come after the Large Hadron Collider, which utilizes low-temperature superconductors.
Lanthanum decahydride is a polyhydride or superhydride compound of lanthanum and hydrogen (LaH10) that has shown evidence of being a high-temperature superconductor. It was the first metal superhydride to be theoretically predicted, synthesized, and experimentally confirmed to superconduct at near room-temperatures. It has a superconducting transition temperature TC around 250 K (−23 °C; −10 °F) at a pressure of 150 gigapascals (22×106 psi), and its synthesis required pressures above approximately 160 gigapascals (23×106 psi).
Metallization pressure is the pressure required for a non-metallic chemical element to become a metal. Every material is predicted to turn into a metal if the pressure is high enough, and temperature low enough. Some of these pressures are beyond the reach of diamond anvil cells, and are thus theoretical predictions. Neon has the highest metallization pressure for any element.
The Bridgman Award is a prize given every two years by the International Association for the Advancement of High Pressure Science and Technology (AIRAPT) for research in the physics, chemistry, or technology of high pressure science. The award is named in honor of Percy Williams Bridgman, Nobel Prize winner and famous pioneer of the physics of high pressure.
Eva Dagmara Zurek is a theoretical chemist, solid-state physicist and materials scientist. As a professor of chemistry at the University at Buffalo, Zurek studies the electronic structure, properties, and reactivity of a wide variety of materials using quantum mechanical calculations. She is interested in high pressure science, superhard, superconducting, quantum and planetary materials, catalysis, as well as solvated electrons and electrides. She develops algorithms to predict the structures of crystals, interfaces them with machine learning models, and applies them in materials discovery.
References
- ↑ Liu, Hanyu; Naumov, Ivan I.; Hoffmann, Roald; Ashcroft, N. W.; Hemley, Russell J. (2017-07-03). "Potential high- T c superconducting lanthanum and yttrium hydrides at high pressure". Proceedings of the National Academy of Sciences. 114 (27): 6990–6995. doi: 10.1073/pnas.1704505114 . ISSN 0027-8424. PMC 5502634 . PMID 28630301.
- ↑ Somayazulu, Maddury; Ahart, Muhtar; Mishra, Ajay K.; Geballe, Zachary M.; Baldini, Maria; Meng, Yue; Struzhkin, Viktor V.; Hemley, Russell J. (2019-01-14). "Evidence for Superconductivity above 260 K in Lanthanum Superhydride at Megabar Pressures". Physical Review Letters. 122 (2): 027001. arXiv: 1808.07695 . Bibcode:2019PhRvL.122b7001S. doi:10.1103/PhysRevLett.122.027001. PMID 30720326.
- ↑ CV, Russell J. Hemley
- ↑ Mao, Bell, Hemley Ultrahigh pressures: Optical observations and Raman measurements of hydrogen and deuterium to 1.47 Mbar, Physical Review Letters, vol. 55, 1985, pp. 99-102, doi : 10.1103/PhysRevLett.55.99 followed by numerous related studies, summarized in Mao, Hemley Ultrahigh pressure transformations in solid hydrogen, Reviews of Modern Physics, vol. 66, 1994, pp. 671–692 doi : 10.1103/RevModPhys.66.671
- ↑
- ↑ Russell Hemley Appointed Director of Carnegie's Geophysical Laboratory, carnegiescience.edu, 5 February 2007
