title: Spin manipulation of free two-dimensional electrons in Si/SiGe quantum wells.
abstract: Understanding the mechanisms controlling the spin coherence of electrons in semiconductors is essential for designing structures for quantum computing applications. Using a pulsed electron paramagnetic resonance spectrometer, we measure spin echoes and deduce a spin coherence time (T2) of up to 3 mus for an ensemble of free two-dimensional electrons confined in a Si/SiGe quantum well. The decoherence can be understood in terms of momentum scattering causing fluctuating effective Rashba fields. Further confining the electrons into a nondegenerate (other than spin) ground state of a quantum dot can be expected to eliminate this decoherence mechanism.
authors.affiliation: Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544 USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Tyryshkin
authors.forename: S A
authors.initials: SA
authors.lastname: Lyon
authors.forename: W
authors.initials: W
authors.lastname: Jantsch
authors.forename: F
authors.initials: F
authors.lastname: Schäffler