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Gelabert M.M.,University of the Balearic Islands | Serra L.,University of the Balearic Islands | Serra L.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib
Physica Scripta | Year: 2012

We present calculations of the g factors of hole quantum wires for a magnetic field in the vertical (growth) direction. The energy bands are symmetric with respect to wavenumber inversion and the obtained g factors are larger than those for in-plane fields. For high-enough wire deformations, the g-factors are quenched when the Rashba interaction is increased. A Rashba-induced anisotropy similar to the horizontal one is thus predicted. A simple perturbative model explains qualitatively the numerical results. © 2012 The Royal Swedish Academy of Sciences. Source


Alomar M.I.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib | Alomar M.I.,University of the Balearic Islands | Lim J.S.,Korea Institute for Advanced Study | Sanchez D.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib | Sanchez D.,University of the Balearic Islands
Journal of Physics: Conference Series | Year: 2015

We investigate the time-dependent response of an interacting mesoscopic capacitor using the Floquet-Green function formalism applied to a single-level Anderson model. We obtain closed expressions for the current and the occupation valid for arbitrary values of the applied ac potential in the limit of small frequencies. In the noninteracting case, we obtain nonsinusoidal responses when the ac amplitude allows crossings between the dot level and the Fermi energy of the attached reservoir. For interacting electrons treated within the Hartree approximation, we self-consistently calculate the capacitor current as a function of time and find a decrease of the peak amplitudes due to the on-site Coulomb repulsion. Source


Hwang S.-Y.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib | Hwang S.-Y.,Pohang University of Science and Technology | Lopez R.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib | Lopez R.,University of California at Santa Barbara | And 3 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

We consider spin-polarized transport in a quantum spin Hall antidot system coupled to normal leads. Due to the helical nature of the conducting edge states, the screening potential at the dot region becomes spin dependent without external magnetic fields nor ferromagnetic contacts. Therefore, the electric current due to voltage or temperature differences becomes spin polarized, its degree of polarization being tuned with the dot level position or the base temperature. This spin-filter effect arises in the nonlinear transport regime only and has a purely interaction origin. Likewise, we find a spin polarization of the heat current, which is asymmetric with respect to the bias direction. Interestingly, our results show that a pure spin current can be generated by thermoelectric means: when a temperature gradient is applied, the created thermovoltage (Seebeck effect) induces a spin-polarized current for vanishingly small charge current. An analogous effect can be observed for the heat transport: a pure spin heat flows in response to a voltage shift even if the thermal current is zero. © 2014 American Physical Society. Source


Arguello-Luengo J.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib | Sanchez D.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib | Lopez R.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib
Physical Review B - Condensed Matter and Materials Physics | Year: 2015

We investigate the heat flow between different terminals in an interacting coherent conductor when inelastic scattering is present. We illustrate our theory with a two-terminal quantum dot setup. Two types of heat asymmetries are investigated: electric asymmetry ΔE, which describes deviations of the heat current in a given contact when voltages are exchanged, and contact asymmetry ΔC, which quantifies the difference between the power measured in two distinct electrodes. In the linear regime, both asymmetries agree and are proportional to the Seebeck coefficient, the latter following at low temperature a Mott-type formula with a dot transmission renormalized by inelasticity. Interestingly, in the nonlinear regime of transport we find ΔE≠ΔC and this asymmetry departure depends on the applied bias configuration. Our results may be important for the recent experiments by Lee et al. [Nature (London) 498, 209 (2013)NATUAS0028-083610.1038/nature12183], where these asymmetries were measured. © 2015 American Physical Society. Source


Lim J.S.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib | Lopez R.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib | Lopez R.,University of the Balearic Islands | Serra L.,Institute Of Fisica Interdisciplinaria I Sistemes Complexos Ifisc Csic Uib | Serra L.,University of the Balearic Islands
New Journal of Physics | Year: 2012

This paper presents a coupled channel model for transport in twodimensional semiconductor Majorana nanowires coupled to normal leads. When the nanowire hosts a zero-mode pair, conspicuous signatures of the linear conductance are predicted. An effective model in second quantization allowing a fully analytical solution is used to clarify the physics. We also discuss the nonlinear current response (dI /dV). © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Source

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