Real-Time Transport Through Magnetic Quantum Dots

Quantum dots are versatile objects of research to explore fundamental questions of quantum physics and are promising candidates for the construction of novel spintronic devices. In particular, small magnetic dots manufactured from diluted magnetic semiconductors using standard lithographic methods, allow for an all-electrical control of the magnetisation and magnetic properties of spintronic devices. Quantum effects play an essential role in such systems. Yet, not many theoretical frameworks exist that allow to explore their correlated real-time dynamics beyond linear response and perturbation theory. What is the role of quantum correlations and how are they affected by the coupling of the quantum system to the macroscopic environment? To provide answers to these questions, the author Daniel Becker extends the method of iterative summation of path integrals (ISPI) to systems containing a quantum spin. This allows to study the interplay between (long-time) spin dynamics and the nonequilibrium charge current through small magnetic quantum dots even in the previously inaccessible regime, where all relevant energies are of the same order of magnitude.