We study the vacuum structure of three-dimensional SU(N) gauge theory coupled to a Chern-Simons term at level k and to F fundamental Dirac fermions. We use a large N holographic description based on a D3/D7 system in type IIB string theory compactified on a supersymmetry breaking circle. The multiple vacua of the theory and the transitions between them are nicely captured by the dual holographic background. The resulting phase diagram, which we derive both at leading and first subleading orders in the 1/N expansion, shows a rich structure where topological field theories, non-linear sigma models and first-order phase transitions appear.
