Manipulating Quantum Information with Semiconductor Spintronics
University of California at Santa Barbara, US
Keywords: manipulating quantum information, semiconductor spintronics
Control over spins in the solid state forms the basis for nascent spintronics and quantum information technologies. There is a growing interest in the use of electronic and nuclear spins in semiconductor nanostructures as a medium for the manipulation and storage of both classical and quantum information . Spin-based electronics offer remarkable opportunities for exploiting the robustness of quantum spin states by combining standard electronics with spin-dependent effects that arise from the interactions between electrons, nuclei, and magnetic fields. Here we provide an overview of recent developments in coherent electronic spin dynamics in semiconductors and quantum structures, including a discussion of temporally- and spatially-resolved magneto-optical measurements that reveal an interesting interplay between electronic and nuclear spins. In particular, we present an electrical scheme for local spin manipulation based on g-tensor modulation resonance (g-TMR), functionally equivalent to electron spin resonance (ESR) but without the use of time-dependent magnetic fields . The technique of g-TMR enables three-dimensional control of electron spins in nanometer-scale geometries using a single voltage signal. These results provide a compelling proof of concept that quantum spin information can be locally manipulated using high-speed electrical circuits. Furthermore, recent measurements of hybrid ferromagnet/semiconductor heterostructures under optical illumination reveal that nuclear spins become highly polarized at low temperatures . We explore the potential for exploiting this behavior to create complex nuclear domains and arrays in lithographically patterned structures. A time-resolved polarization microscope is used to directly image the nuclear landscape in hybrid nanostructures, demonstrating the ability to design and control polarization patterns in the semiconductor. These experiments investigate the electronic, photonic, and magnetic manipulation of electron and nuclear spins in a variety of semiconductor structures and focus on investigating the underlying physics for quantum information processing in the solid state.
 Semiconductor Spintronics and Quantum Computation, Series on Nanoscience and Technology, ed. D.D. Awschalom, D. Loss, N. Samarth (Springer-Verlag, Berlin, 2002).
 Y. Kato et al., “Gigahertz electron spin manipulation using g-tensor modulation resonance”, submitted for publication (2002).
 R.J. Epstein et al., “Spontaneous spin coherence in n-GaAs produced by ferromagnetic proximity polarization”, Phys. Rev. B. 65, 121202 (R), (2002).
NSTI Nanotech 2003 Conference Technical Program Abstract