arXiv subjects

N. M. Gergs

Publications and source records attributed to N. M. Gergs.

2 recordsLinked to original sources

arXiv2019

Long-lived circulating currents in strongly correlated nanorings

We study the time evolving currents flowing in an interacting, ring-shaped nanostructure after a bias voltage has been switched on. The source-to-drain current exhibits the expected relaxation towards its quasi-static equilibrium value at a rate $Γ_0$ reflecting the lead-induced broadening of the ring states. In contrast, the current circulating within the ring decays with a different rate $Γ$, which is a rapidly decaying function of the interaction strength and thus can take values orders of magnitude below $Γ_0$. This implies the existence of a regime in which the nanostructure is far from equilibrium even though the transmitted current is already stationary. We discuss experimental setups to observe the long-lived ring transients.

cond-mat.mes-hall↗

arXiv2018

Spin switching via quantum dot spin valves

We develop a theory for spin transport and magnetization dynamics in a quantum-dot spin valve, i.e., two magnetic reservoirs coupled to a quantum dot. Our theory is able to take into account effects of strong correlations. We demonstrate that, as a result of these strong correlations, the dot gate voltage enables control over the current-induced torques on the magnets, and, in particular, enables voltage-controlled magnetic switching. The electrical resistance of the structure can be used to read out the magnetic state. Our model may be realized by a number of experimental systems, including magnetic scanning-tunneling microscope tips and artificial quantum dot systems.

cond-mat.mes-hall↗