Electric-dipole-induced spin resonance in quantum dots

An alternating electric field, applied to a quantum dot, couples to the electron spin via the spin-orbit interaction. We analyze different types of spin-orbit coupling known in the literature and find two efficient mechanisms of spin control in quantum dots. The linear in momentum Dresselhaus and Rashba spin-orbit couplings give rise to a fully transverse effective magnetic field in the presence of a Zeeman splitting at lowest order in the spin-orbit interaction. The cubic in momentum Dresselhaus terms are efficient in a quantum dot with anharmonic confining potential and give rise to a spin-electric coupling proportional to the orbital magnetic field. We derive an effective spin Hamiltonian, which can be used to implement spin manipulation on a time scale of $10\mathrm{ns}$ with the current experimental setups.

Figure 1

Schematic of a setup for electric field control of spin via the spin-orbit interaction. The quantum dot (QD) contains a single electron with spin $\mathit{S}=(\hslash ∕2)\mathit{\sigma }$, deep in the Coulomb blockade valley. The gates 1 and 2 are used to generate an alternating electric field $\mathit{E}\left(t\right)$, which acts via the spin-orbit interaction on the electron spin. As a result, an electric dipole spin resonance (EDSR) occurs if the frequency of $\mathit{E}\left(t\right)$ is tuned to match the Larmor frequency ${\omega }_Z=E_Z∕\hslash$.