Chapter 1 Single Spin Coherence in Semiconductors

Abstract

Publisher Summary Spins in semiconductors offer a pathway toward the integration of information storage and processing in a single material. In this chapter, the focus is on three varieties of single spin systems in semiconductors that can be optically probed and manipulated. Single electron spins in GaAs quantum dots are discussed. The single electron spin state can be sequentially initialized, manipulated, and read out using all-optical techniques. The spins are probed using time-resolved Kerr rotation, which allows for the coherent evolution of a single electron spin to be observed, revealing a coherence time of ∼10 ns at 10 K. By applying off-resonant, picosecond-scale optical pulses, the spins can be manipulated via the optical Stark effect. Magnetic ions are discussed as spin recombination centers in semiconductor quantum wells. The magnetization of few magnetic ions can be controlled at zero-field for these normally paramagnetic spins and can, in principle, be extended to the single-ion limit. These spins might be considered the most strongly coupled system in which strong exchange interactions couple the spin state of the magnetic ions to the band carriers. Single nitrogen-vacancy centers in the wide bandgap semiconductor diamond are described. These spins represent the opposite end of the spectrum with a spin that is relatively uncoupled to the host band structure resulting in record room temperature spin coherence times of >350 μs. This enables traditional magnetic resonance techniques to be used for nitrogen-vacancy (NV) spin manipulation.