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Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter, especially the solid and liquid phases which arise from electromagnetic forces between atoms. More generally, the subject deals with condensed phases of matter: systems of many constituents with strong interactions among them. More exotic condensed phases include the superconducting phase exhibited by certain materials at extremely low cryogenic temperature, the ferromagnetic and antiferromagnetic phases of spins on crystal lattices of atoms, and the Bose–Einstein condensate found in ultracold atomic systems. Condensed matter physicists seek to understand the behavior of these phases by experiments to measure various material properties, and by applying the physical laws of quantum mechanics, electromagnetism, statistical mechanics, and other physics theories to develop mathematical models.
Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike an ordinary metallic conductor, whose resistance decreases gradually as its temperature is lowered, even down to near absolute zero, a superconductor has a characteristic critical temperature below which the resistance drops abruptly to zero. An electric current through a loop of superconducting wire can persist indefinitely with no power source.
Unconventional superconductors are materials that display superconductivity which does not conform to conventional BCS theory or its extensions.
High-temperature superconductors are defined as materials with critical temperature above 77 K, the boiling point of liquid nitrogen. They are only "high-temperature" relative to previously known superconductors, which function at even colder temperatures, close to absolute zero. The "high temperatures" are still far below ambient, and therefore require cooling. The first break through 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.
A room-temperature superconductor is a material capable of displaying superconductivity at temperatures above 0 °C, 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.
In condensed matter physics, a pseudogap describes a state where the Fermi surface of a material possesses a partial energy gap, for example, a band structure state where the Fermi surface is gapped only at certain points.
In superconductivity, a semifluxon is a half integer vortex of supercurrent carrying the magnetic flux equal to the half of the magnetic flux quantum Φ0. Semifluxons exist in the 0-π long Josephson junctions at the boundary between 0 and π regions. This 0-π boundary creates a π discontinuity of the Josephson phase. The junction reacts to this discontinuity by creating a semifluxon. Vortex's supercurrent circulates around 0-π boundary. In addition to semifluxon, there exist also an antisemifluxon. It carries the flux −Φ0/2 and its supercurrent circulates in the opposite direction.
In a standard superconductor, described by a complex field fermionic condensate wave function, vortices carry quantized magnetic fields because the condensate wave function is invariant to increments of the phase by . There a winding of the phase by creates a vortex which carries one flux quantum. See quantum vortex.
Ferromagnetic superconductors are materials that display intrinsic coexistence of ferromagnetism and superconductivity. They include UGe2, URhGe, and UCoGe. Evidence of ferromagnetic superconductivity was also reported for ZrZn2 in 2001, but later reports question these findings. These materials exhibit superconductivity in proximity to a magnetic quantum critical point.
The 122 iron arsenide unconventional superconductors are part of a new class of iron-based superconductors. They form in the tetragonal I4/mmm, ThCr2Si2 type, crystal structure. The shorthand name "122" comes from their stoichiometry; the 122s have the chemical formula AEFe2Pn2, where AE stands for alkaline earth metal (Ca, Ba, Sr or Eu) and Pn is pnictide (As, P, etc.). These materials become superconducting under pressure and also upon doping. The maximum superconducting transition temperature found to date is 38 K in the Ba0.6K0.4Fe2As2. The microscopic description of superconductivity in the 122s is yet unclear.
Piers Coleman is a British-born theoretical physicist, working in the field of theoretical condensed matter physics. Coleman is professor of physics at Rutgers University in New Jersey and at Royal Holloway, University of London.
The Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) phase can arise in a superconductor in large magnetic field. Among its characteristics are Cooper pairs with nonzero total momentum and a spatially non-uniform order parameter, leading to normal conducting areas in the superconductor.
In the field of unconventional superconductivity, a Fermi arc is a phenomenon visible in the pseudogap state of a superconductor. Seen in momentum space, part of the space exhibits a gap in the density of states, like in a superconductor. This starts at the antinodal points, and spreads through momentum space when lowering the temperature until everywhere is gapped and the sample is superconducting. The area in momentum space that remains ungapped is called the Fermi Arc.
Distrontium ruthenate, also known as strontium ruthenate, is an oxide of strontium and ruthenium with the chemical formula Sr2RuO4. It was the first reported perovskite superconductor that did not contain copper. Strontium ruthenate is structurally very similar to the high-temperature cuprate superconductors, and in particular, is almost identical to the lanthanum doped superconductor (La, Sr)2CuO4. However, the transition temperature for the superconducting phase transition is 0.93 K (about 1.5 K for the best sample), which is much lower than the corresponding value for cuprates.
Jason Joseph William Alexander Robinson is a British academic, and Professor of Materials Physics at the University of Cambridge in the Department of Materials Science & Metallurgy. He is also a Fellow of St John's College, Cambridge. He has worked extensively in the areas of superconductivity, superconducting spintronics, spintronics, magnetism, quantum materials, and nanoelectronics. Particular research topics include the superconductor proximity effect, unconventional superconductivity, quantum and topological transport.
In solid-state physics, the kagome metal or kagome magnet is a type of ferromagnetic quantum material. The atomic lattice in a kagome magnet has layered overlapping triangles and large hexagonal voids, akin to the kagome pattern in traditional Japanese basket-weaving. This geometry induces a flat electronic band structure with Dirac crossings, in which the low-energy electron dynamics correlate strongly.
Dale J. Van Harlingen is an American condensed matter physicist.
A Josephson diode is an electronic device that superconducts electrical current in one direction and is resistive in the other direction. The device is a Josephson junction exhibiting a superconducting diode effect (SDE). It is an example of a quantum material Josephson junction (QMJJ), where the weak link in the junction is a quantum material. The Josephson diode effect can occur in superconducting devices where time reversal symmetry and inversion symmetry are broken.
Pengcheng Dai is a Chinese American experimental physicist and academic. He is the Sam and Helen Worden Professor of Physics in the Department of Physics and Astronomy at Rice University.
Elbio Rubén Dagotto is an Argentinian-American theoretical physicist and academic. He is a distinguished professor in the department of physics and astronomy at the University of Tennessee, Knoxville, and Distinguished Scientist in the Materials Science and Technology Division at the Oak Ridge National Laboratory.
References
- 1 2 Seokjin Bae; Hyunsoo Kim; Yun Suk Eo; Sheng Ran; I-lin Liu; Fuhrman, Wesley T.; Paglione, Johnpierre; Butch, Nicholas P.; Anlage, Steven M. (2021). "Anomalous normal fluid response in a chiral superconductor UTe2". Nature Communications. 12 (1): 2644. Bibcode:2021NatCo..12.2644B. doi:10.1038/s41467-021-22906-6. PMC 8113495 . PMID 33976162.
- "Unconventional superconductor acts the part of a promising quantum computing platform". EurekAlert! (Press release). 15 July 2021.
- ↑ Sheng Ran; I-Lin Liu; Yun Suk Eo; Campbell, Daniel J.; Neves, Paul M.; Fuhrman, Wesley T.; Saha, Shanta R.; Eckberg, Christopher; Hyunsoo Kim; Graf, David; Balakirev, Fedor; Singleton, John; Paglione, Johnpierre; Butch, Nicholas P. (2019). "Extreme magnetic field-boosted superconductivity". Nature Physics. 15 (12): 1250–1254. arXiv: 1905.04343 . Bibcode:2019NatPh..15.1250R. doi:10.1038/s41567-019-0670-x. PMC 8201648 . PMID 34131432.
- "'Lazarus Superconductivity' Observed – Rare Phenomenon Called Re-Entrant Superconductivity". SciTechDaily. October 7, 2019.
- ↑ Rosa, Priscila F. S.; Weiland, Ashley; Fender, Shannon S.; Scott, Brian L.; Ronning, Filip; Thompson, Joe D.; Bauer, Eric D.; Thomas, Sean M. (2022-05-23). "Single thermodynamic transition at 2 K in superconducting UTe2 single crystals". Communications Materials. 3 (1): 33. arXiv: 2110.06200 . Bibcode:2022CoMat...3...33R. doi:10.1038/s43246-022-00254-2. ISSN 2662-4443. S2CID 248970170.
- ↑ Aishwarya, Anuva; May-Mann, Julian; Raghavan, Arjun; Nie, Laimei; Romanelli, Marisa; Ran, Sheng; Saha, Shanta R.; Paglione, Johnpierre; Butch, Nicholas P.; Fradkin, Eduardo; Madhavan, Vidya (June 2023). "Magnetic-field-sensitive charge density waves in the superconductor UTe2". Nature. 618 (7967): 928–933. arXiv: 2207.09491 . Bibcode:2023Natur.618..928A. doi:10.1038/s41586-023-06005-8. ISSN 1476-4687. PMID 37380690. S2CID 250698906.
- ↑ Gu, Qiangqiang; Carroll, Joseph P.; Wang, Shuqiu; Ran, Sheng; Broyles, Christopher; Siddiquee, Hasan; Butch, Nicholas P.; Saha, Shanta R.; Paglione, Johnpierre; Davis, J. C. Séamus; Liu, Xiaolong (June 2023). "Detection of a pair density wave state in UTe2". Nature. 618 (7967): 921–927. arXiv: 2209.10859 . Bibcode:2023Natur.618..921G. doi:10.1038/s41586-023-05919-7. ISSN 1476-4687. PMC 10307636 . PMID 37380691.
- ↑ "Breakthrough identifies new state of topological quantum matter | Cornell Chronicle". news.cornell.edu. Retrieved 2023-08-04.
- ↑ "Topological superconductor harbours unusual crystalline state". Physics World. 2023-08-03. Retrieved 2023-08-03.
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