Electron-Nuclear Spin Manipulation in Semiconductor Quantum Dots by Electrical Current


In this project we intend to control the electron-nuclear spin dynamics in negatively charged quantum dots by a combination of optical and electrical driving pulses. One key ingredient is the usage of self-assembled II-VI quantum dot structures (CdSe/ZnSe, ZnO/ZnMgO) where the number of nuclear spins seen by the resident electron is in the range of 100 or even below. Optical pumping allows thus for the creation of a dynamical nuclear polarization on a time scale as short as a few tens of microseconds without the need of an external magnetic field. The other key ingredient is the usage of micro-/nanoscale coils and wires on top of the semiconductor for the application of current-induced magnetic fields. In contrast to large-scale external Helmholtz coils, miniaturized coils and wires exhibit much smaller inductivities and, therefore, are capable of transient magnetic pulses down to the nanosecond regime as well as the generation of ac fields with frequencies up to 1 GHz and amplitudes of 10 mT and beyond. The combination of both features will enable us to perform new types of experiments where tailored optical and electrical pulse sequences are being used for the manipulation of the electron-nuclear spin system. Issues to be addressed are such as coherent electron-nuclear spin states, nuclear spin heating and Rabi oscillations. Elucidation of these new types of dynamical scenarios represents a starting point for the implementation of quantum logical functions based on the electron-nuclear spin ensemble in quantum dots.
In this project we intend to control the electron-nuclear spin dynamics in negatively charged quantum dots by a combination of optical and electrical driving pulses. One key ingredient is the usage of self-assembled II-VI quantum dot structures (CdSe/ZnSe, ZnO/ZnMgO) where the number of nuclear spins seen by the resident electron is in the range of 100 or even below. Optical pumping allows thus for the creation of a dynamical nuclear polarization on a time scale as short as a few tens of microseconds without the need of an external magnetic field. The other key ingredient is the usage of micro-/nanoscale coils and wires on top of the semiconductor for the application of current-induced magnetic fields. In contrast to large-scale external Helmholtz coils, miniaturized coils and wires exhibit much smaller inductivities and, therefore, are capable of transient magnetic pulses down to the nanosecond regime as well as the generation of ac fields with frequencies up to 1 GHz and amplitudes of 10 mT and beyond. The combination of both features will enable us to perform new types of experiments where tailored optical and electrical pulse sequences are being used for the manipulation of the electron-nuclear spin system. Issues to be addressed are such as coherent electron-nuclear spin states, nuclear spin heating and Rabi oscillations. Elucidation of these new types of dynamical scenarios represents a starting point for the implementation of quantum logical functions based on the electron-nuclear spin ensemble in quantum dots.


Principal investigators
Henneberger, Fritz Prof. Dr. sc. nat. (Details) (Experimental Physics / Physical Foundations of Photonics)

Duration of project
Start date: 08/2011
End date: 07/2013

Last updated on 2022-09-09 at 03:06