Unconventional superconductors are materials that display superconductivity which does not conform to either the conventional BCS theory or Nikolay Bogolyubov's theory or its extensions.
High-temperature superconductors are defined as materials that behave as superconductors at temperatures above 77 K, the boiling point of liquid nitrogen. The adjective "high temperature" is only in respect to previously known superconductors, which function at even colder temperatures close to absolute zero. In absolute terms, these "high temperatures" are still far below ambient, and therefore require cooling. The first high-temperature superconductor was discovered in 1986, by IBM researchers Bednorz and Müller, who 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.
Ivar Giaever is a Norwegian-American engineer and physicist who shared the Nobel Prize in Physics in 1973 with Leo Esaki and Brian Josephson "for their discoveries regarding tunnelling phenomena in solids". Giaever's share of the prize was specifically for his "experimental discoveries regarding tunnelling phenomena in superconductors".
Scanning probe microscopy (SPM) is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. SPM was founded in 1981, with the invention of the scanning tunneling microscope, an instrument for imaging surfaces at the atomic level. The first successful scanning tunneling microscope experiment was done by Gerd Binnig and Heinrich Rohrer. The key to their success was using a feedback loop to regulate gap distance between the sample and the probe.
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.
A Josephson junction is a quantum mechanical device which is made of two superconducting electrodes separated by a barrier. A π Josephson junction is a Josephson junction in which the Josephson phase φ equals π in the ground state, i.e. when no external current or magnetic field is applied.
In condensed matter physics, scanning SQUID microscopy is a technique where a superconducting quantum interference device (SQUID) is used to image surface magnetic field strength with micrometre-scale resolution. A tiny SQUID is mounted onto a tip which is then rastered near the surface of the sample to be measured. As the SQUID is the most sensitive detector of magnetic fields available and can be constructed at submicrometre widths via lithography, the scanning SQUID microscope allows magnetic fields to be measured with unparalleled resolution and sensitivity. The first scanning SQUID microscope was built in 1992 by Black et al. Since then the technique has been used to confirm unconventional superconductivity in several high-temperature superconductors including YBCO and BSCCO compounds.
Juan Carlos Campuzano is a Paraguayan American physicist. He is a Distinguished Professor of Physics at the University of Illinois at Chicago. He was a Distinguished Fellow at Argonne National Laboratory, and a he is also a 2001 American Physical Society Fellow and a recipient of the 2011 Oliver Buckley Prize in Condensed Matter Physics. He is an expert in high-temperature superconductivity.
Steven M. Girvin is an American physicist who is the Eugene Higgins Professor of Physics at Yale University and who served as deputy provost for research at Yale from 2007 to 2017. Girvin is noted for his theoretical work on quantum many body systems such as the fractional quantum Hall effect, and as co-developer of circuit QED, the application of the ideas of quantum optics to superconducting microwave circuits. Circuit QED is now the leading architecture for construction of quantum computers based on superconducting qubits.
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.
Kathryn Ann Moler is an American physicist, and current Dean of Research at Stanford University. She received her BSc (1988) and Ph.D. (1995) from Stanford University. After working as a visiting scientist at IBM T.J. Watson Research Center in 1995, she held a postdoctoral position at Princeton University from 1995-1998. She joined the faculty of Stanford University in 1998, and became an Associate in CIFAR's Superconductivity Program in 2000. She became an Associate Professor at Stanford in 2002 and is currently a Professor of Applied Physics and of Physics at Stanford. She currently works in the Geballe Laboratory for Advanced Materials (GLAM), and is the Director of the Center for Probing the Nanoscale (CPN), a National Science Foundation-funded center where Stanford and IBM scientists continue to improve scanning probe methods for measuring, imaging, and controlling nanoscale phenomena. She lists her scientific interests and main areas of research and experimentation as:
Jochen Mannhart is a German physicist.
Gerald J. Dolan was an American solid state physicist.
Elihu Abrahams was a theoretical physicist, specializing in condensed matter physics.
Antonio Barone was an Italian physicist. He was Emeritus Professor of the Federico II University of Naples and Director of the CNR Cybernetics Institute in Arco Felice (Naples), Italy. He is best known for his work on superconductivity and Josephson effect.
Zhi-Xun Shen is a Chinese-American experimental and solid state physicist who is a professor at Stanford University. He is particularly noted for his ARPES studies on high-temperature superconductors.
J. C. Séamus Davis is an Irish physicist whose research explores the world of macroscopic quantum physics. Davis concentrates upon the fundamental physics of exotic states of electronic, magnetic, atomic and space-time quantum matter. A specialty is development of innovative instrumentation to allow direct atomic-scale visualization or perception of the quantum many-body phenomena that are characteristic of these states.
Aharon Kapitulnik is an Israeli-American experimental condensed matter physicist working at Stanford University. He is known primarily for his work on strongly correlated electron systems, low dimensional electronic systems, unconventional superconductors, topological superconductors, superconductivity and magnetism, transport in bad metals and precision measurements.
Dale J. Van Harlingen is an American condensed matter physicist.
Allen Marshall Goldman is an American experimental condensed matter physicist, known for his research on electronic transport properties of superconductors and for the eponymous Carlson-Goldman mode involving collective oscillations in superconductors.
