  We investigate the electric manipulation of a single electron spin in a
single gate-defined quantum dot. We observe that so-far neglected differences
between the hyperfine and spin-orbit mediated electric dipole spin resonance
conditions have important consequences at high magnetic fields. In experiments
using adiabatic rapid passage to invert the electron spin, we observe an
unusually wide and asymmetric response as a function of magnetic field.
Simulations support the interpretation of the lineshape in terms of four
different resonance conditions. These findings may lead to isotope-selective
control of dynamic nuclear polarization in quantum dots.
