New $\mathcal{N}=(0,4)$ AdS$_3$ near-horizons in Type IIB

We construct new families of $\mathcal{N}=(0,4)$ $\mathrm{AdS}_3\times S^2 \times \tilde S^2 \times S^1$ backgrounds fibred over a 2d Riemann surface in Type IIB string theory. These solutions are obtained by extracting the near-horizon limit of D3-brane box configurations, consisting on D3-D5-NS5 branes ending on D5'-NS5' background branes. We relate our families of solutions to previous $\mathrm{AdS}_3\times S^2 \times \text{CY}_2$ and $\mathrm{AdS}_3\times S^3 \times S^2$ solutions to Type IIA recently constructed in the literature. We construct explicit 2d quiver CFTs associated to the D3-brane box configurations, and check that the central charges match the holographic result. We extend our solutions to include D7-branes, and show that a subclass of these solutions can be interpreted in terms of D3-D5-NS5 defect branes embedded in a 5d fixed point theory. This is explicitly realised by linking our solutions to a 6d domain wall that asymptotes locally the $\mathrm{AdS}_6\times S^2 \times \Sigma_2$ solution T-dual to the Brandhuber-Oz vacuum.