Joseph Pingenot

Method for full Bloch sphere control of a localized spin via a single electrical gate

Manipulating individual spins in semiconductors requires quickly and coherently reorienting localized spins while leaving neighboring spins unaffected. Difficulties confining oscillating magnetic fields have motivated alternate approaches that use electric fields to change the local magnetic environment, including moving an electron within a hyperfine field gradient or fringe-field gradient. Higher temperatures require spins to be localized in much smaller quantum dots, however, where these techniques are less effective. In contrast, g tensor manipulation techniques couple an electric field to the spin via the spin-orbit interaction, and should be scalable to small dots with strong confinement. We describe a device design which permits coherent, non-resonant manipulation of a single electron spin to point in any direction using only a static magnetic field and a single vertical electrical gate.

Method for Full Bloch-Sphere Control of a Localized Spin via a Single Electrical Gate

Manipulating individual spins in semiconductors requires quickly and coherently reorienting localized spins while leaving neighboring spins unaffected. Difficulties confining oscillating magnetic fields have motivated alternate approaches that use electric fields to change the local magnetic environment, including moving an electron within a hyperfine field gradient or fringe-field gradient. Higher temperatures require spins to be localized in much smaller quantum dots, however, where these techniques are less effective. In contrast, g tensor manipulation techniques couple an electric field to the spin via the spin-orbit interaction, and should be scalable to small dots with strong confinement. We describe a device design which permits coherent, non-resonant manipulation of a single electron spin to point in any direction using only a static magnetic field and a single vertical electrical gate.

Manipulation of Individual Electronic Spins in Semiconductors

Manipulating individual spins in a solid, such as for quantum information processing or a spintronic device, requires the ability to quickly and coherently reorient a spin while leaving its neighbors unaffected. Using traditional electron spin resonance methods is problematic because of the difficulty of confining oscillating magnetic fields to small volumes. In contrast, g-tensor modulation resonance, which has been demonstrated in quantum wells, uses the electric field to exploit differences in the spin-orbit interaction in and around the confining structure and should be scalable. I will present theoretical calculations of g-tensor modulation resonance spin manipulation in quantum dots and donors and show that such schemes are feasible for manipulation of single spins. For InAs/GaAs quantum dots it is possible to rapidly reorient the spin in an arbitrary direction with only the application of a static magnetic field and the application of pulsed electric fields from a gate. Donors behave much like quantum dots, with the advantage that they do not suffer from variations in composition and size.