|
Meir-Wingreen Formula
The Meir-Wingreen formula describes the electric current through an arbitrary mesoscopic system. It was formulated by Yigal Meir and Ned Wingreen. When the interaction between electrons is neglected, this formula reduces to the Landauer formula. This textbook formula has become a standard tool for calculating the current through various systems, such as molecular junctions, quantum dot Quantum dots (QDs) are semiconductor particles a few nanometres in size, having light, optical and electronics, electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanote ...s and nanoscale devices. References Electric current Mesoscopic physics {{electronics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Current
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In an electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons. The SI unit of electric current is the ampere, or ''amp'', which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit. Electric current is measured using a device called an ammeter. Electric currents create magnetic fields, which are used in motors, generators, inductors, and transformers. In ordinary con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesoscopic
Mesoscopic physics is a subdiscipline of condensed matter physics that deals with materials of an intermediate size. These materials range in size between the nanoscale for a quantity of atoms (such as a molecule) and of materials measuring micrometres. The lower limit can also be defined as being the size of individual atoms. At the micrometre level are bulk materials. Both mesoscopic and macroscopic objects contain many atoms. Whereas average properties derived from constituent materials describe macroscopic objects, as they usually obey the laws of classical mechanics, a mesoscopic object, by contrast, is affected by thermal fluctuations around the average, and its electronic behavior may require modeling at the level of quantum mechanics.Sci-Tech Dictionary. McGraw-Hill Dictionary of Scientific and Technical Terms. 2003. McGraw-Hill Companies, Inc A macroscopic electronic device, when scaled down to a meso-size, starts revealing quantum mechanical properties. For example, at ... [...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] |
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] |
Landauer Formula
The Landauer formula—named after Rolf Landauer, who first suggested its prototype in 1957—is a formula relating the electrical resistance of a quantum conductor to the scattering properties of the conductor. In the simplest case where the system only has two terminals, and the scattering matrix of the conductor does not depend on energy, the formula reads : G(\mu) = G_0 \sum_n T_n (\mu) \ , where G is the electrical conductance, G_0 = e^2/(\pi\hbar) \approx 7.75\times 10^ \Omega^ is the conductance quantum, T_n are the transmission eigenvalues of the channels, and the sum runs over all transport channels in the conductor. This formula is very simple and physically sensible: The conductance of a nanoscale conductor is given by the sum of all the transmission possibilities that an electron has when propagating with an energy equal to the chemical potential, E=\mu . A generalization of the Landauer formula for multiple probes is the Landauer–Büttiker formula, proposed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Dot
Quantum dots (QDs) are semiconductor particles a few nanometres in size, having light, optical and electronics, electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconductor, semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band. The excited electron can drop back into the valence band releasing its energy as light. This light emission (photoluminescence) is illustrated in the figure on the right. The color of that light depends on the energy difference between the conductance band and the valence band, or the transition between discrete energy states when band structure is no longer a good definition in QDs. In the language of materials science, nanoscale semiconductor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanoscale Device
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] |
Electric Current
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In an electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons. The SI unit of electric current is the ampere, or ''amp'', which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit. Electric current is measured using a device called an ammeter. Electric currents create magnetic fields, which are used in motors, generators, inductors, and transformers. In ordinary con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
