Collaborative Research: Collective and Coherent Spin Organization in Magnetic Semiconductor Nanostructures

This experimental project explores collective and coherent spin behavior of electrons, local moments and nuclear spins in low dimensional systems ranging from 2D electron gases to 0D quantum dots. The experiments focus on model nanostructures fabricated from II-VI magnetic semiconductors which can be systematically tailored to modulate spin interactions between confined electronic states, magnetic ions and nuclei. The project combines development of sophisticated nanostructures and state-of-the-art spin probes having high temporal (~100 fs) and spatial (~100 nm) resolution, and high magnetic moment sensitivity (~105 Bohr magnetons). Microfabricated cantilevers will be used to search for collective spin effects in magnetic semiconductor nanostructures. Dynamical spin organization in these nanostructures will be studied using an 'all-optical' magnetic resonance technique, encompassing spin precession of electrons, local moments and nuclear spins. Coherent optical spectroscopy coupled with time-resolved transport will probe dynamical spin transport in mesoscopic systems (wires) wherein the nuclear polarization is systematically varied using optical pumping. Finally, near field scanning optical resonance techniques will be developed to achieve spatially resolved magnetic resonance imaging of 2D electron spin systems. Knowledge of the collective spin response in nanostructures gained from this project may be important for coherent control of spin processes in future generations of magneto-electronic devices. Advanced technical training in solid state physics, materials science, and advanced instrumentation will prepare students for careers in academic and industrial environments.

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This experimental condensed matter physics project explores the complex quantum mechanical behavior of electrons, magnetic atoms and nuclei in low dimensional systems ranging from 'electron sheets' (2D electron gases) to 'electron boxes' (0D quantum dots). The experiments use model nanostructures fabricated from a family of materials (II-VI magnetic semiconductors) in which the quantum mechanical property known as 'spin' can be systematically varied. A fundamental understanding of spin transport in nanostructures may enable new technologies based on quantum mechanical interactions in the solid state. The project is comprised of a collaborative effort that combines development of sophisticated nanostructures with state-of-the-art spin probes having high temporal (~100 femtoseconds) and spatial (~100 nanometer) resolution, and high spin sensitivity (~ 105 magnetic atoms). Experiments range from ultrasensitive magnetometry, to 'all-optical' spin resonance microscopy, to dynamical studies of electron spin transport. While the principal focus is on fundamental physics, knowledge gained will be important for developing concepts in the coherent control of spin processes in future generations of high speed magneto-electronic devices, with potential applications ranging from ultrafast switching to quantum computation. This research involves advanced technical training in materials physics and advanced instrumentation, and prepares students to make immediate contributions both in academic and industrial environments.