A crystallographic defect is an interruption of the regular patterns of arrangement of atoms or molecules in crystalline solids. The positions and orientations of particles,which are repeating at fixed distances determined by the unit cell parameters in crystals,exhibit a periodic crystal structure,but this is usually imperfect. Several types of defects are often characterized:point defects,line defects,planar defects,bulk defects. Topological homotopy establishes a mathematical method of characterization.
A quasiperiodic crystal,or quasicrystal,is a structure that is ordered but not periodic. A quasicrystalline pattern can continuously fill all available space,but it lacks translational symmetry. While crystals,according to the classical crystallographic restriction theorem,can possess only two-,three-,four-,and six-fold rotational symmetries,the Bragg diffraction pattern of quasicrystals shows sharp peaks with other symmetry orders—for instance,five-fold.
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.
The Schön scandal concerns German physicist Jan Hendrik Schön who briefly rose to prominence after a series of apparent breakthroughs with semiconductors that were later discovered to be fraudulent. Before he was exposed,Schön had received the Otto-Klung-Weberbank Prize for Physics and the Braunschweig Prize in 2001,as well as the Outstanding Young Investigator Award of the Materials Research Society in 2002,all of which were later rescinded.
An amorphous metal is a solid metallic material,usually an alloy,with disordered atomic-scale structure. Most metals are crystalline in their solid state,which means they have a highly ordered arrangement of atoms. Amorphous metals are non-crystalline,and have a glass-like structure. But unlike common glasses,such as window glass,which are typically electrical insulators,amorphous metals have good electrical conductivity and can show metallic luster.
Marvin Lou Cohen is an American–Canadian theoretical physicist. He is a physics professor at the University of California,Berkeley. Cohen is a leading expert in the field of condensed matter physics. He is widely known for his seminal work on the electronic structure of solids.
Subir Sachdev is Herchel Smith Professor of Physics at Harvard University specializing in condensed matter. He was elected to the U.S. National Academy of Sciences in 2014,and received the Lars Onsager Prize from the American Physical Society and the Dirac Medal from the ICTP in 2018. He was a co-editor of the Annual Review of Condensed Matter Physics from 2017–2019.
A topological insulator is a material whose interior behaves as an electrical insulator while its surface behaves as an electrical conductor,meaning that electrons can only move along the surface of the material.
Nicholas Harrison FRSC FinstP is an English theoretical physicist known for his work on developing theory and computational methods for discovering and optimising advanced materials. He is the Professor of Computational Materials Science in the Department of Chemistry at Imperial College London where he is co-director of the Institute of Molecular Science and Engineering.
Robert William Boyd is an American physicist noted for his work in optical physics and especially in nonlinear optics. He is currently the Canada Excellence Research Chair Laureate in Quantum Nonlinear Optics based at the University of Ottawa,professor of physics cross-appointed to the school of electrical engineering and computer science at the University of Ottawa,and professor of optics and professor of physics at the University of Rochester.
Mechanical metamaterials are artificial structures with mechanical properties defined by their structure rather than their composition. They can be seen as a counterpart to the rather well-known family of optical metamaterials. They are often also termed elastodynamic metamaterials and include acoustic metamaterials as a special case of vanishing shear. Their mechanical properties can be designed to have values which cannot be found in nature.
Samarium hexaboride (SmB6) is an intermediate-valence compound where samarium is present both as Sm2+ and Sm3+ ions at the ratio 3:7. It is a Kondo insulator having a metallic surface state.
The interface between lanthanum aluminate (LaAlO3) and strontium titanate (SrTiO3) is a notable materials interface because it exhibits properties not found in its constituent materials. Individually,LaAlO3 and SrTiO3 are non-magnetic insulators,yet LaAlO3/SrTiO3 interfaces can exhibit electrical metallic conductivity,superconductivity,ferromagnetism,large negative in-plane magnetoresistance,and giant persistent photoconductivity. The study of how these properties emerge at the LaAlO3/SrTiO3 interface is a growing area of research in condensed matter physics.
Ali Alavi FRS is a professor of theoretical chemistry in the Department of Chemistry at the University of Cambridge and a Director of the Max Planck Institute for Solid State Research in Stuttgart.
Fullerides are chemical compounds containing fullerene anions. Common fullerides are derivatives of the most common fullerenes,i.e. C60 and C70. The scope of the area is large because multiple charges are possible,i.e.,[C60]n− (n = 1,2...6),and all fullerenes can be converted to fullerides. The suffix "-ide" implies their negatively charged nature.
Antonio Helio de Castro Neto is a Brazilian-born physicist. He is the founder and director of the Centre for Advanced 2D Materials at the National University of Singapore. He is a condensed matter theorist known for his work in the theory of metals,magnets,superconductors,graphene and two-dimensional materials. He is a distinguished professor in the Departments of Materials Science Engineering,and Physics and a professor at the Department of Electrical and Computer Engineering. He was elected as a fellow of the American Physical Society in 2003. In 2011 he was elected as a fellow of the American Association for the Advancement of Science.
David Tománek (born July 1954) is a U.S.-Swiss physicist of Czech origin and researcher in nanoscience and nanotechnology. He is Emeritus Professor of Physics at Michigan State University. He is known for predicting the structure and calculating properties of surfaces,atomic clusters including the C60 buckminsterfullerene,nanotubes,nanowires and nanohelices,graphene,and two-dimensional materials including phosphorene.
Alessio Zaccone is an Italian physicist.
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. Neon has the highest metallization pressure for any element.
Dov I. Levine is an American-Israeli physicist,known for his research on quasicrystals,soft condensed matter physics,and statistical mechanics out of equilibrium.
