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Molecular Circuit
Molecular scale electronics, also called single-molecule electronics, is a branch of nanotechnology that uses single molecules, or nanoscale collections of single molecules, as electronic components. Because single molecules constitute the smallest stable structures imaginable, this miniaturization is the ultimate goal for shrinking electrical circuits. The field is often termed simply as "molecular electronics", but this term is also used to refer to the distantly related field of conductive polymers and organic electronics, which uses the properties of molecules to affect the bulk properties of a material. A nomenclature distinction has been suggested so that ''molecular materials for electronics'' refers to this latter field of bulk applications, while ''molecular scale electronics'' refers to the nanoscale single-molecule applications treated here. Fundamental concepts Conventional electronics have traditionally been made from bulk materials. Ever since their invention in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanotechnology
Nanotechnology, also shortened to nanotech, is the use of matter on an atomic, molecular, and supramolecular scale for industrial purposes. The earliest, widespread description of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as molecular nanotechnology. A more generalized description of nanotechnology was subsequently established by the National Nanotechnology Initiative, which defined nanotechnology as the manipulation of matter with at least one dimension sized from 1 to 100 nanometers (nm). This definition reflects the fact that quantum mechanical effects are important at this quantum-realm scale, and so the definition shifted from a particular technological goal to a research category inclusive of all types of research and technologies that deal with the special properties of matter which occur below the given size threshold. It is therefore common to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron's mass is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum ( spin) of a half-integer value, expressed in units of the reduced Planck constant, . Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: They can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conjugated System
In theoretical chemistry, a conjugated system is a system of connected p-orbitals with delocalized electrons in a molecule, which in general lowers the overall energy of the molecule and increases stability. It is conventionally represented as having alternating single and multiple bonds. Lone pairs, radicals or carbenium ions may be part of the system, which may be cyclic, acyclic, linear or mixed. The term "conjugated" was coined in 1899 by the German chemist Johannes Thiele. Conjugation is the overlap of one p-orbital with another across an adjacent σ bond (in transition metals, d-orbitals can be involved). A conjugated system has a region of overlapping p-orbitals, bridging the interjacent locations that simple diagrams illustrate as not having a π bond. They allow a delocalization of π electrons across all the adjacent aligned p-orbitals. The π electrons do not belong to a single bond or atom, but rather to a group of atoms. Molecules containing conjugated syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yigal Meir
Yigal Meir (20 November 1957) is the Graham Beck professor of Quantum Science and Technology at Ben Gurion University, specializing in condensed matter; in particular mesoscopic physics, disordered systems and strongly correlated materials. Among his achievements is the derivation of the Meir-Wingreen Formula, and solving the 0.7 anomaly puzzle in quantum point contacts. Career Meir was educated in Tel Aviv University, where he obtained a PhD in theoretical condensed matter physics under the supervision of Amnon Aharony and Yoseph Imry. He held postdoctoral positions at MIT (1989–91), with Patrick Lee, and at the University of California at Santa Barbara (1991–94), with Walter Kohn. In 1994 he joined the physics department at Ben Gurion University, Beersheba, Israel as a faculty member. He holds a visiting position at Princeton University. Meir has published more than 120 papers in refereed journals. Early in his career, he concentrated on transport through quantum dot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ned Wingreen
Ned S. Wingreen is a theoretical physicist and the Howard A. Prior Professor of the Life Sciences at Princeton University. He is a member of the Department of Molecular Biology and of the Lewis-Sigler Institute for Integrative Genomics, where he is currently director of graduate studies. He is the associate director of the Princeton Center for Theoretical Science, and is also associated faculty in the department of physics. Working with Yigal Meir, Wingreen formulated the Meir-Wingreen Formula which describes the electric current through an arbitrary mesoscopic system. Education and career Wingreen received a B.S. in physics from California Institute of Technology in 1984. Wingreen then received his Ph.D. in theoretical condensed matter physics from Cornell University in 1989 as a Hertz Fellow. His dissertation was titled "Resonant Tunneling with Electron-Phonon Interaction" and he was advised by John W. Wilkins. He did his postdoc in mesoscopic physics at MIT. There, along with Y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonid Keldysh
Leonid Veniaminovich Keldysh (; 7 April 1931 – 11 November 2016) was a Soviet and Russian physicist. Keldysh was a professor in the I.E. Tamm Theory division of the Lebedev Physical Institute of the Russian Academy of Sciences in Moscow and a faculty member at Texas A&M University. He was known for developing the Keldysh formalism, a powerful quantum field theory framework designed to describe a system in a non-equilibrium state, as well as for the theory of excitonic insulators (Keldysh-Kopaev model, with Yuri Kopaev). Keldysh's awards include the 2009 Rusnanoprize, an international nanotechnology award, for his work related to molecular-beam epitaxy, the 2011 Evgenii Feinberg Memorial Medal, and the 2015 Lomonosov Grand Gold Medal of the Russian Academy of Sciences. Keldysh was a son of mathematician Lyudmila Keldysh. His uncle, Mstislav Keldysh, was a mathematician and the president of the Academy of Sciences of the Soviet Union. Sergei Novikov, a mathematician and a Field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gordon Baym
Gordon Alan Baym (born July 1, 1935) is an American theoretical physicist. Biography Born in New York City, he graduated from the Brooklyn Technical High School, and received his undergraduate degree from Cornell University in 1956. He earned his Ph.D. from Harvard University in 1960, studying under Julian Schwinger. He joined the physics faculty of the University of Illinois at Urbana-Champaign in 1963, becoming a full professor in 1968. His areas of research include condensed-matter physics, nuclear physics and astrophysics, as well as the history of physics. In 1962 he and Leo Kadanoff collaborated on ''Quantum Statistical Mechanics: Green's Function Methods in Equilibrium and Nonequilibrium Problems''. In 1969 he published ''Lectures on Quantum Mechanics'', a widely used graduate textbook that, unconventionally, begins with photon polarization. In 1991 he and Chris Pethick published the monograph ''Landau Fermi-Liquid Theory: Concepts and Applications''. Baym was award ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leo Kadanoff
Leo Philip Kadanoff (January 14, 1937 – October 26, 2015) was an American physicist. He was a professor of physics (emeritus from 2004) at the University of Chicago and a former President of the American Physical Society (APS). He contributed to the fields of statistical physics, chaos theory, and theoretical condensed matter physics. Biography Kadanoff was raised in New York City. He received his undergraduate degree and doctorate in physics (1960) from Harvard University. After a post-doctorate at the Niels Bohr Institute in Copenhagen, he joined the physics faculty at the University of Illinois in 1965. Kadanoff's early research focused upon superconductivity. In the late 1960s, he studied the organization of matter in phase transitions. Kadanoff demonstrated that sudden changes in material properties (such as the magnetization of a magnet or the boiling of a fluid) could be understood in terms of scaling and universality. With his collaborators, he showed how all the expe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Green's Function
In mathematics, a Green's function is the impulse response of an inhomogeneous linear differential operator defined on a domain with specified initial conditions or boundary conditions. This means that if \operatorname is the linear differential operator, then * the Green's function G is the solution of the equation \operatorname G = \delta, where \delta is Dirac's delta function; * the solution of the initial-value problem \operatorname y = f is the convolution (G \ast f). Through the superposition principle, given a linear ordinary differential equation (ODE), \operatorname y = f, one can first solve \operatorname G = \delta_s, for each , and realizing that, since the source is a sum of delta functions, the solution is a sum of Green's functions as well, by linearity of . Green's functions are named after the British mathematician George Green, who first developed the concept in the 1820s. In the modern study of linear partial differential equations, Green's functions are s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolf Landauer
Rolf William Landauer (February 4, 1927 – April 27, 1999) was a German-American physicist who made important contributions in diverse areas of the thermodynamics of information processing, condensed matter physics, and the conductivity of disordered media. In 1961 he discovered Landauer's principle, that in any logically irreversible operation that manipulates information, such as erasing a bit of memory, entropy increases and an associated amount of energy is dissipated as heat. This principle is relevant to reversible computing, quantum information and quantum computing. He also is responsible for the Landauer formula relating the electrical resistance of a conductor to its scattering properties. He won the Stuart Ballantine Medal of the Franklin Institute, the Oliver Buckley Prize of the American Physical Society and the IEEE Edison Medal, among many other honors. Biography Landauer was born on February 4, 1927, in Stuttgart, Germany. He emigrated to the United States in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variational Principle
In science and especially in mathematical studies, a variational principle is one that enables a problem to be solved using calculus of variations, which concerns finding functions that optimize the values of quantities that depend on those functions. For example, the problem of determining the shape of a hanging chain suspended at both ends—a catenary—can be solved using variational calculus, and in this case, the variational principle is the following: The solution is a function that minimizes the gravitational potential energy of the chain. Overview Any physical law which can be expressed as a variational principle describes a self-adjoint operator. These expressions are also called Hermitian. Such an expression describes an invariant under a Hermitian transformation. History Felix Klein's Erlangen program attempted to identify such invariants under a group of transformations. In what is referred to in physics as Noether's theorem, the Poincaré group of transformations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
