We study quantum Hall ferromagnets with a finite density of topologically charged spin textures in the presence of internal degrees of freedom such as spin, valley, or layer indices, so that the system is parametrized by a $d$-component spinor field. In the absence of anisotropies we find a hexagonal Skyrmion lattice that completely breaks the underlying $SU(d)$ symmetry with the low-lying excitation spectrum separating into $d^2-1$ gapless acoustic magnetic modes and a magnetophonon. The ground state charge density modulations, which inevitably exist in these lattices, vanish exponentially in $d$. We discuss the role of effective mass anisotropy for $SU(3)$-valley Skyrmions relevant to experiments with AlAs quantum wells. Here we find a transition which breaks a sixfold rotational symmetry of the triangular lattice, followed by the formation of a square lattice at large values of anisotropy strength.

• Received 17 July 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.186802