Spintronics,also known as spin electronics,is the study of the intrinsic spin of the electron and its associated magnetic moment,in addition to its fundamental electronic charge,in solid-state devices. The field of spintronics concerns spin-charge coupling in metallic systems;the analogous effects in insulators fall into the field of multiferroics.
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.
Magnetic semiconductors are semiconductor materials that exhibit both ferromagnetism and useful semiconductor properties. If implemented in devices,these materials could provide a new type of control of conduction. Whereas traditional electronics are based on control of charge carriers,practical magnetic semiconductors would also allow control of quantum spin state. This would theoretically provide near-total spin polarization,which is an important property for spintronics applications,e.g. spin transistors.
Gallium manganese arsenide,chemical formula (Ga,Mn)As is a magnetic semiconductor. It is based on the world's second most commonly used semiconductor,gallium arsenide,,and readily compatible with existing semiconductor technologies. Differently from other dilute magnetic semiconductors,such as the majority of those based on II-VI semiconductors,it is not paramagnetic but ferromagnetic,and hence exhibits hysteretic magnetization behavior. This memory effect is of importance for the creation of persistent devices. In (Ga,Mn)As,the manganese atoms provide a magnetic moment,and each also acts as an acceptor,making it a p-type material. The presence of carriers allows the material to be used for spin-polarized currents. In contrast,many other ferromagnetic magnetic semiconductors are strongly insulating and so do not possess free carriers. (Ga,Mn)As is therefore a candidate material for spintronic devices but it is likely to remain only a testbed for basic research as its Curie temperature could only be raised up to approximately 200 K.
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..
Resonant inelastic X-ray scattering (RIXS) is an advanced X-ray spectroscopy technique.
Superstripes is a generic name for a phase with spatial broken symmetry that favors the onset of superconducting or superfluid quantum order. This scenario emerged in the 1990s when non-homogeneous metallic heterostructures at the atomic limit with a broken spatial symmetry have been found to favor superconductivity. Before a broken spatial symmetry was expected to compete and suppress the superconducting order. The driving mechanism for the amplification of the superconductivity critical temperature in superstripes matter has been proposed to be the shape resonance in the energy gap parameters ∆n that is a type of Fano resonance for coexisting condensates.
In condensed matter physics,a quantum spin liquid is a phase of matter that can be formed by interacting quantum spins in certain magnetic materials. Quantum spin liquids (QSL) are generally characterized by their long-range quantum entanglement,fractionalized excitations,and absence of ordinary magnetic order.
The Rashba effect,also called Bychkov–Rashba effect,is a momentum-dependent splitting of spin bands in bulk crystals and low-dimensional condensed matter systems similar to the splitting of particles and anti-particles in the Dirac Hamiltonian. The splitting is a combined effect of spin–orbit interaction and asymmetry of the crystal potential,in particular in the direction perpendicular to the two-dimensional plane. This effect is named in honour of Emmanuel Rashba,who discovered it with Valentin I. Sheka in 1959 for three-dimensional systems and afterward with Yurii A. Bychkov in 1984 for two-dimensional systems.
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.
Electric dipole spin resonance (EDSR) is a method to control the magnetic moments inside a material using quantum mechanical effects like the spin–orbit interaction. Mainly,EDSR allows to flip the orientation of the magnetic moments through the use of electromagnetic radiation at resonant frequencies. EDSR was first proposed by Emmanuel Rashba.
Oxyarsenides or arsenide oxides are chemical compounds formally containing the group AsO,with one arsenic and one oxygen atom. The arsenic and oxygen are not bound together as in arsenates or arsenites,instead they make a separate presence bound to the cations (metals),and could be considered as a mixed arsenide-oxide compound. So a compound with OmAsn requires cations to balance a negative charge of 2m+3n. The cations will have charges of +2 or +3. The trications are often rare earth elements or actinides. They are in the category of oxypnictide compounds.
John F. Mitchell is an American chemist and researcher. He is the deputy director of the materials science division at the U.S. Department of Energy's (DOE) Argonne National Laboratory and leads Argonne's Emerging Materials Group.
Amnon Aharony is an Israeli Professor (Emeritus) of Physics in the School of Physics and Astronomy at Tel Aviv University,Israel and in the Physics Department of Ben Gurion University of the Negev,Israel. After years of research on statistical physics,his current research focuses on condensed matter theory,especially in mesoscopic physics and spintronics. He is a member of the Israel Academy of Sciences and Humanities,a Foreign Honorary Member of the American Academy of Arts and Sciences and of several other academies. He also received several prizes,including the Rothschild Prize in Physical Sciences,and the Gunnar Randers Research Prize,awarded every other year by the King of Norway.
The FLEUR code is an open-source scientific software package for the simulation of material properties of crystalline solids,thin films,and surfaces. It implements Kohn-Sham density functional theory (DFT) in terms of the all-electron full-potential linearized augmented-plane-wave method. With this,it is a realization of one of the most precise DFT methodologies. The code has the common features of a modern DFT simulation package. In the past,major applications have been in the field of magnetism,spintronics,quantum materials,e.g. in ultrathin films,complex magnetism like in spin spirals or magnetic Skyrmion lattices,and in spin-orbit related physics,e.g. in graphene and topological insulators.
Maria Roser Valentí is a Spanish-Catalonian professor of theoretical condensed matter physics at Johann Wolfgang Goethe-Universität Frankfurt am Main.
Fractional Chern insulators (FCIs) are lattice generalizations of the fractional quantum Hall effect that have been studied theoretically since 1993 and have been studied more intensely since early 2010. They were first predicted to exist in topological flat bands carrying Chern numbers. They can appear in topologically non-trivial band structures even in the absence of the large magnetic fields needed for the fractional quantum Hall effect. In principle,they can also occur in partially filled bands with trivial band structures if the inter-electron interaction is unusual. They promise physical realizations at lower magnetic fields,higher temperatures,and with shorter characteristic length scales compared to their continuum counterparts. FCIs were initially studied by adding electron-electron interactions to a fractionally filled Chern insulator,in one-body models where the Chern band is quasi-flat,at zero magnetic field. The FCIs exhibit a fractional quantized Hall conductance.
In condensed matter physics,altermagnetism is a type of persistent magnetic state in ideal crystals. Altermagnetic structures are collinear and crystal-symmetry compensated,resulting in zero net magnetisation. Unlike in an ordinary collinear antiferromagnet,another magnetic state with zero net magnetization,the electronic bands in an altermagnet are not Kramers degenerate,but instead depend on the wavevector in a spin-dependent way. Related to this feature,key experimental observations were published in 2024. It has been speculated that altermagnetism may have applications in the field of spintronics.
This is an incomplete list of works by John B. Goodenough. His academic output has been described as "prolific".
