Spin Dynamics of Electrons Confined in Silicon Heterostructures
Electron spin states in silicon heterostructures show promise as qubits for quantum information processing. The small spin-orbit interaction and low concentration of silicon isotopes with a nuclear spin lead to long lived electron spin states in these materials. Recently, a host of single and few electron silicon quantum device architectures have arisen as implementations for quantum computation. Conventional X-band (10 GHz) Electron Spin Resonance (ESR) is a natural method to probe the dynamics of electron spin states in silicon heterostructures to better understand the materials limitations on spin coherence. We have used these techniques to characterize and study interface disorder and material quality in silicon heterostructures. Additionally, we have fabricated large area ensembles of gate defined Si/SiGe quantum dots (~ few x 10^8 dots with a lithographic diameter of 150 nm and a 500 nm period) and use ESR to study their relaxation and decoherence mechanisms. Long single electron relaxation (1 ms) and coherence times (310 μs) have been observed at 350 mK, showing promise for future silicon quantum device architectures.