Gate control of spin dynamics in III-V semiconductor quantum dots

We show that the g factor and the spin-flip time $T_1$ of a heterojunction quantum dot is very sensitive to the band-bending interface electric field even in the absence of wave-function penetration into the barrier. When this electric field is of the order of ${10}^5\mathrm{V}/\mathrm{c}\mathrm{m},$ g and $T_1$ show high sensitivity to dot radius and magnetic field arising from the interplay between Rashba and Dresselhaus spin-orbit interactions. This result opens new possibilities for the design of a quantum dot spin quantum computer, where g factor and $T_1$ can be engineered by manipulating the spin-orbit coupling through external gates.