J. N. H. J. Cremers | Searcharxiv

arXiv2001

Weak localization and conductance fluctuations of a chaotic quantum dot with tunable spin-orbit coupling

In a two-dimensional quantum dot in a GaAs heterostructure, the spin-orbit scattering rate is substantially reduced below the rate in a bulk two-dimensional electron gas [B.I. Halperin et al, Phys. Rev. Lett. 86, 2106 (2001)]. Such a reduction can be undone if the spin-orbit coupling parameters acquire a spatial dependence, which can be achieved, e.g., by a metal gate covering only a part of the quantum dot. We calculate the effect of such spatially non-uniform spin-orbit scattering on the weak localization correction and the universal conductance fluctuations of a chaotic quantum dot coupled to electron reservoirs by ballistic point contacts, in the presence of a magnetic field parallel to the plane of the quantum dot.

cond-mat.mes-hall↗

arXiv2001

Dephasing in a quantum pump

We study how dephasing affects the distribution of the dc current pumped through a chaotic quantum dot. We introduce dephasing by the addition of a voltage probe to the quantum dot, treating both the case of controlled dephasing (when the voltage probe is coupled to the dot via a ballistic point contact with a conductance that is increased stepwise) and intrinsic dephasing (for which the voltage probe serves as a phenomelogical model). While dephasing eventually suppresses the dc current through the dot, we also find that, for a quantum dot with single-mode point contacts, a small amount of dephasing actually decreases the likelihood of a zero pumped current.

cond-mat.mes-hall↗