Deforming D-brane models on $T^6\mathrm{/}({\mathbb{Z}}_2\times {\mathbb{Z}}_{2M})$ orbifolds

We review the stabilisation of complex structure moduli in Type IIA orientifolds, especially on $T^6 / ($\mathbb{Z}$_2 \times $\mathbb{Z}$_6^\prime \times \Omega $\mathcal{R}$)$withdiscretetorsion,viadeformationsof$$\mathbb{Z}$_2 \times $\mathbb{Z}$_2$ orbifold singularities. While D6-branes in SO(2N) and USp(2N) models always preserve supersymmetry and thus give rise to flat directions, in an exemplary Pati-Salam model with only U(N) gauge groups ten out of the 15 deformation moduli can be stabilised at the orbifold point.