Dynamical spin Hall conductivity in a magnetic disordered system
FIG. 1 : Schematic geometry of the spin Hall effect; a longitudinal current jx driven by an external electric field induces a transversal spin current that results in a polarization of the carrier spins following the sign of their momentum (spheres with arrows). We investigate the intrinsic spin Hall effect in a quantum well semiconductor...
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Enhanced thermopower in the transient regime
Fig.1: Increase of the Seebeck coefficient in the transient regime of a metal/dot/metal junction. Collaboration with A. Crépieux, CPT Marseille We derived formal expressions of time-dependent energy and heat currents through a nanoscopic device using the Keldysh nonequilibrium Green function technique. Numerical results are reported for a metal/dot/metal junction where the dot level energy is...
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Modeling of p-type MOS transistors
Fig. 1: Illustration of the multi-band effect on the local density of states and transmission coefficient in a Si p-type double-gate MOSFET whose transport direction is along [100]. VDS = -0.4V and VG = 0V. For sake of clarity the bandstructures and potentials are represented in terms of hole energy [1,2]. Complementary metal oxide semi-conductor...
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Quantum modeling of thin film solar cells
Fig. 1: Current spectrum calculated in a thin film (180 nm) GaAs solar cell. The corresponding PCE is 8.8%. In addition to the expected positive current we show a negative contribution at the device edges (labeled as LEC for Large Energy Contribution). Carriers generated at energy larger than the junction barrier are less sensitive to...
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Quantum PV effect in hetero-nanowire junctions
Following that idea of combining one-dimensional and zero-dimensional nanostructures, like in photonics devices, we investigated the photovoltaic response of a mesoscopic junction in which the light is absorbed in a quantum dot laterally connected to two quantum wires on each side Fig. 1. The transport and optical properties have then been determined using a powerful...
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One-shot current conserving inelastic transport modeling
Fig.1: Illustration of the current degradation in double-gate MOSFETs resulting from electron-phonon interactions. In this case the one-shot LOA+AC method perfectly reproduces the SCBA results [2]. We describe a lowest-order approximation (LOA) to the nonequilibrium Green’s function in the presence of interactions, and generally address how one can build Phi-derivable one-shot approximations that satisfy the...
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