  We report experiments on epitaxially grown Fe/GaAs/Au tunnel junctions
demonstrating that the tunneling anisotropic magnetoresistance (TAMR) effect
can be controlled by a magnetic field. Theoretical modelling shows that the
interplay of the orbital effects of a magnetic field and the Dresselhaus
spin-orbit coupling in the GaAs barrier leads to an independent contribution to
the TAMR effect with uniaxial symmetry, whereas the Bychkov-Rashba spin-orbit
coupling does not play a role. The effect is intrinsic to barriers with bulk
inversion asymmetry.
