High Field Phenomena of Qubits

Abstract

Electron and nuclear spins are very promising candidates to serve as quantum bits (qubits) for proposed quantum computers, as the spin degrees of freedom are relatively isolated from their surroundings, and can be coherently manipulated e.g. through pulsed EPR and NMR. For solid state spin systems, impurities in crystals based on carbon and silicon in various forms have been suggested as qubits, and very long relaxation rates have been observed in such systems. We have investigated a variety of these systems at high magnetic fields in our multi-frequency pulsed EPR/ENDOR spectrometer. A high magnetic field leads to large electron spin polarizations at helium temperatures giving rise to various phenomena that are of interest with respect to quantum computing. For example, it allows the initialization of the both the electron spin as well as hyperfine-coupled nuclear spins in a well defined state by combining millimeter and RF radiation; it can increase the T2 relaxation times by eliminating decoherence due to dipolar interaction; and it can lead to new mechanisms for the coherent electrical readout of electron spins. We will show some examples of these and other effects in Si:P, SiC:N, and nitrogen-related centers in diamond.

13 pages, 5 figures. Confererence Proceedings of the 6th Asia-Pacific ESR/EPR Society Conference in Cairns, Australia (2008)

References in corpus (10)

• Single-shot read-out of an individual electron spin in a quantum dot
• Quenching Spin Decoherence in Diamond through Spin Bath Polarization
• Electrically-detected magnetic resonance in ion-implanted Si:P nanostructures
• A multi-frequency high-field pulsed EPR / ENDOR spectrometer
• Electrical detection of spin echoes for phosphorus donors in silicon
• Efficient Dynamic Nuclear Polarization at High Magnetic Fields
• Long spin coherence in silicon with an electrical spin trap readout
• Spin-dependent processes at the crystalline Si-SiO_2 interface at high magnetic fields
• Electron Spin Relaxation and 39K Pulsed ENDOR Studies on Cr5+ doped K3NbO8 at 9.7 and 240 GHz
• Dynamic nuclear polarization with simultaneous excitation of electronic and nuclear transitions

Cited by in corpus (10)

• Isolated electron spins in silicon carbide with millisecond-coherence times
• Polytype control of spin qubits in silicon carbide
• Electrically and mechanically tunable electron spins in silicon carbide color centers
• Optical polarization of nuclear spins in silicon carbide
• Initializing, manipulating and storing quantum information with bismuth dopants in silicon
• Coherent electrical readout of defect spins in 4H-SiC by photo-ionization at ambient conditions
• A high-frequency electron paramagnetic resonance spectrometer for multi-dimensional, -frequency and -phase pulsed measurements
• Efficient Dynamic Polarization of Phosphorus Nuclei in Silicon in Strong Magnetic Fields and Low Temperatures
• Electrically detected spin echoes of donor nuclei in silicon
• The spin relaxation of nitrogen donors in 6H SiC crystals as studied by the electron spin echo method