| 1. |
- Antonyuk, Vadim, et al.
(författare)
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Effect of electron-phonon interaction on electron conductance in one-dimensional systems
- 2004
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 69:15
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the effect of electron-phonon interaction on the electronic transport in a one-dimensional wire where both electrons and phonons are quantum confined. We found substeps appeared in the quantized electron conductance, and the step height depends on the electron-phonon coupling strength. With increasing temperature, the substep structure smooths out. Dependent on the transmission probability through the wire, this substep correction can be either positive or negative. In the limiting cases we reproduce the existing results.
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| 2. |
- Chang, CH, et al.
(författare)
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Spin relaxation dynamics of quasiclassical electrons in ballistic quantum dots with strong spin-orbit coupling
- 2004
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 70:24
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Tidskriftsartikel (refereegranskat)abstract
- We performed path integral simulations of spin evolution controlled by the Rashba spin-orbit interaction in the semiclassical regime for chaotic and regular quantum dots. The spin polarization dynamics have been found to be strikingly different from the D'yakonov-Perel' (DP) spin relaxation in bulk systems. Also an important distinction has been found between long time spin evolutions in classically chaotic and regular systems. In the former case the spin polarization relaxes to zero within relaxation time much larger than the DP relaxation, while in the latter case it evolves to a time independent residual value. The quantum mechanical analysis of the spin evolution based on the exact solution of the Schrodinger equation with Rashba SOI has confirmed the results of the classical simulations for the circular dot, which is expected to be valid in general regular systems. In contrast, the spin relaxation down to zero in chaotic dots contradicts what has to be expected from quantum mechanics. This signals on the importance of quantum effects missed in the semiclassical simulations for long time spin dynamics.
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| 3. |
- Chang, CH, et al.
(författare)
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Spin transmission through quantum dots with strong spin-orbit interaction
- 2004
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Ingår i: Physics Letters. Section A: General, Atomic and Solid State Physics. - : Elsevier BV. - 0375-9601. ; 326:5-6, s. 436-441
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Tidskriftsartikel (refereegranskat)abstract
- Quantum oscillations of the spin conductance through regular and chaotic 2D quantum dots under the varying Rashba spin-orbit interaction and at zero magnetic field have been investigated numerically by summing up the spin evolution matrices for classical transmitting trajectories. The Fourier analysis of these oscillations indicates a strong geometry dependence of the power spectra. The spectra for narrow rings are dominated by a single peak as previous analytic result, for regular quantum dots are represented by multiple peaks, and for chaotic quantum dots by quasi-continuum peaks.
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| 4. |
- Larsson, Magnus, et al.
(författare)
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Thermionic phenomena in a nanoscale ring without carrier reservoirs: A thermionic couple
- 2004
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 70:23
-
Tidskriftsartikel (refereegranskat)abstract
- We have studied various thermionic processes in a small one-dimensional ring consisting of a metallic wire and an insulator which serves as the potential barrier for the charge carriers in the metallic wire. The ring is not connected to any particle reservoir, but at the two junctions it is attached to two phonon reservoirs with different temperatures. The lengths of both the metallic wire and the insulating part are shorter than the carrier mean free path, and therefore the nonequilibrium electron distribution function was solved using the Boltzmann-equation approach with electron-phonon interaction at the two junctions. We found that there is always a heat current flowing from the hot junction to the cold one. The electric current over the potential barrier increases monotonically as the Fermi energy in the metallic wire approaches the potential barrier height from below. Using a modulation doped semiconductor ring for numerical calculation, the thermionic current is found to be almost linear with respect to the temperature difference between the two junctions. Consequently, our system can be developed into a nanometer scale thermionic couple.
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