New AdS₃/CFT₂ pairs in massive IIA with (0, 4) and (4, 4) supersymmetries

We construct a new class of AdS₃ × S³ × M₄ solutions of massive Type IIA supergravity with (0, 4) supersymmetries and SU(3) structure. We study in detail two subclasses of these solutions. The first subclass is when M₄ = S²× Σ₂, with Σ₂ a 2d Riemann surface, and the geometry is foliated over the Σ₂. We interpret these solutions as duals to surface defect CFTs within the 6d (1, 0) CFTs dual to the AdS₇ × S² × I solutions of massive IIA supergravity. The second subclass is when M₄ = T³ × I and the geometry is foliated over the interval. In this case supersymmetry is enhanced to (4, 4) in the massless limit, and the solutions are the sought-for holographic duals of (4, 4) CFTs living in two dimensional D2-NS5-D4 Hanany-Witten brane set-ups. In turn, in the massive case the solutions find an interpretation as D2-D4 branes embedded in Type I’ string theory. We construct explicit quiver gauge theories from the different brane set-ups that flow in the IR to the 2d dual CFTs dual to the solutions. We check the validity of our proposals with the matching between the field theory and holographic central charges.