  Based on a detailed theoretical examination of the lattice distortion in
high-index epilayers in terms of continuum mechanics, expressions are deduced
that allow the calculation and experimental determination of the strain tensor
for (hhl)-oriented (Ga,Mn)As layers. Analytical expressions are derived for the
strain-dependent free-energy density and for the resistivity tensor for
monoclinic and orthorhombic crystal symmetry, phenomenologically describing the
magnetic anisotropy (MA) and anisotropic magnetoresistance (AMR) by appropriate
anisotropy and resistivity parameters, respectively. Applying the results to
(113)A orientation with monoclinic crystal symmetry, the expressions are used
to determine the strain tensor and the shear angle of a series of
(113)A-oriented (Ga,Mn)As layers by high-resolution x-ray diffraction and to
probe the MA and AMR at 4.2 K by means of angle-dependent magnetotransport.
Whereas the transverse resistivity parameters are nearly unaffected by the
magnetic field, the parameters describing the longitudinal resistivity are
strongly field dependent.
