The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Naoufel Ben Abdallah - One of the best experts on this subject based on the ideXlab platform.
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Quantum Transport in Crystals: Effective Mass Theorem and K·P Hamiltonians
Communications in Mathematical Physics, 2011Co-Authors: Luigi Barletti, Naoufel Ben AbdallahAbstract:In this paper the Effective Mass approximation and the k·p multi-band models, describing quantum evolution of electrons in a crystal lattice, are discussed. Electrons are assumed to move in both a periodic potential and a macroscopic one. The typical period $${\epsilon}$$ of the periodic potential is assumed to be very small, while the macroscopic potential acts on a much bigger length scale. Such homogenization asymptotic is investigated by using the envelope-function decomposition of the electron wave function. If the external potential is smooth enough, the k·p and Effective Mass models, well known in solid-state physics, are proved to be close (in the strong sense) to the exact dynamics. Moreover, the position density of the electrons is proved to converge weakly to its Effective Mass approximation.
Jeffrey G Snyder - One of the best experts on this subject based on the ideXlab platform.
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low Effective Mass leading to high thermoelectric performance
Energy and Environmental Science, 2012Co-Authors: Aaron D Lalonde, Heng Wang, Jeffrey G SnyderAbstract:High Seebeck coefficient by creating large density-of-states Effective Mass through either electronic structure modification or manipulating nanostructures is commonly considered as a route to advanced thermoelectrics. However, large density-of-state due to flat bands leads to large transport Effective Mass, which results in a simultaneous decrease of mobility. In fact, the net effect of such a high Effective Mass is a lower thermoelectric figure of merit, zT, when the carriers are predominantly scattered by phonons according to the deformation potential theory of Bardeen–Shockley. We demonstrate that the beneficial effect of light Effective Mass contributes to high zT in n-type thermoelectric PbTe, where doping and temperature can be used to tune the Effective Mass. This clear demonstration of the deformation potential theory to thermoelectrics shows that the guiding principle for band structure engineering should be low Effective Mass along the transport direction.
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low Effective Mass leading to high thermoelectric performance
arXiv: Materials Science, 2011Co-Authors: Aaron D Lalonde, Heng Wang, Jeffrey G SnyderAbstract:High Seebeck coefficient by creating large density of state (DOS) around the Fermi level through either electronic structure modification or manipulating nanostructures, is commonly considered as a route to advanced thermoelectrics. However, large density of state due to flat bands leads to large Effective Mass, which results in a simultaneous decrease of mobility. In fact, the net effect of high Effective Mass is a lower thermoelectric figure of merit when the carriers are predominantly scattered by acoustic phonons according to the deformation potential theory of Bardeen-Shockley. We demonstrate the beneficial effect of light Effective Mass leading to high power factor in n-type thermoelectric PbTe, where doping and temperature can be used to tune the Effective Mass. This clear demonstration of the deformation potential theory to thermoelectrics shows that the guiding principle for band structure engineering should be low Effective Mass along the transport direction.
Reinhard Alkofer - One of the best experts on this subject based on the ideXlab platform.
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Effective Mass signatures in multiphoton pair production
Physical Review Letters, 2014Co-Authors: Christian Kohlf??rst, Holger Gies, Reinhard AlkoferAbstract:Electron-positron pair production in oscillating electric fields is investigated in the nonperturbative threshold regime. Accurate numerical solutions of quantum kinetic theory for corresponding observables are presented and analyzed in terms of a proposed model for an Effective Mass of electrons and positrons acquired within the given strong electric field. Although this Effective Mass cannot provide an exact description of the collective interaction of a charged particle with the strong field, physical observables are identified which carry direct and sensitive signatures of the Effective Mass.
Luigi Barletti - One of the best experts on this subject based on the ideXlab platform.
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Quantum Transport in Crystals: Effective Mass Theorem and K·P Hamiltonians
Communications in Mathematical Physics, 2011Co-Authors: Luigi Barletti, Naoufel Ben AbdallahAbstract:In this paper the Effective Mass approximation and the k·p multi-band models, describing quantum evolution of electrons in a crystal lattice, are discussed. Electrons are assumed to move in both a periodic potential and a macroscopic one. The typical period $${\epsilon}$$ of the periodic potential is assumed to be very small, while the macroscopic potential acts on a much bigger length scale. Such homogenization asymptotic is investigated by using the envelope-function decomposition of the electron wave function. If the external potential is smooth enough, the k·p and Effective Mass models, well known in solid-state physics, are proved to be close (in the strong sense) to the exact dynamics. Moreover, the position density of the electrons is proved to converge weakly to its Effective Mass approximation.
Aaron D Lalonde - One of the best experts on this subject based on the ideXlab platform.
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low Effective Mass leading to high thermoelectric performance
Energy and Environmental Science, 2012Co-Authors: Aaron D Lalonde, Heng Wang, Jeffrey G SnyderAbstract:High Seebeck coefficient by creating large density-of-states Effective Mass through either electronic structure modification or manipulating nanostructures is commonly considered as a route to advanced thermoelectrics. However, large density-of-state due to flat bands leads to large transport Effective Mass, which results in a simultaneous decrease of mobility. In fact, the net effect of such a high Effective Mass is a lower thermoelectric figure of merit, zT, when the carriers are predominantly scattered by phonons according to the deformation potential theory of Bardeen–Shockley. We demonstrate that the beneficial effect of light Effective Mass contributes to high zT in n-type thermoelectric PbTe, where doping and temperature can be used to tune the Effective Mass. This clear demonstration of the deformation potential theory to thermoelectrics shows that the guiding principle for band structure engineering should be low Effective Mass along the transport direction.
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low Effective Mass leading to high thermoelectric performance
arXiv: Materials Science, 2011Co-Authors: Aaron D Lalonde, Heng Wang, Jeffrey G SnyderAbstract:High Seebeck coefficient by creating large density of state (DOS) around the Fermi level through either electronic structure modification or manipulating nanostructures, is commonly considered as a route to advanced thermoelectrics. However, large density of state due to flat bands leads to large Effective Mass, which results in a simultaneous decrease of mobility. In fact, the net effect of high Effective Mass is a lower thermoelectric figure of merit when the carriers are predominantly scattered by acoustic phonons according to the deformation potential theory of Bardeen-Shockley. We demonstrate the beneficial effect of light Effective Mass leading to high power factor in n-type thermoelectric PbTe, where doping and temperature can be used to tune the Effective Mass. This clear demonstration of the deformation potential theory to thermoelectrics shows that the guiding principle for band structure engineering should be low Effective Mass along the transport direction.