Topological band and superconductivity in UTe2

$\mathrm{U}{\mathrm{Te}}_{2}$ is a likely spin-triplet superconductor that also exhibits evidence for chiral Majorana edge states. A characteristic structural feature of $\mathrm{U}{\mathrm{Te}}_{2}$ is inversion-symmetry related pairs of U atoms, forming rungs of ladders. Here we show how each rung's two sublattice degrees of freedom play a key role in understanding the electronic structure and the origin of superconductivity. In particular, $\mathrm{DFT}+U$ calculations generically reveal a topological band near the chemical potential originating from a band inversion associated with $5f$ electrons residing on these rungs, necessitating a microscopic description that includes these rung degrees of freedom. Furthermore, we show that a previously identified strong ferromagnetic interaction within a U-U rung leads to a pseudospin-triplet superconducting state that accounts for a nonzero polar Kerr angle, the observed magnetic field-temperature phase diagrams, and nodal Weyl fermions. Our analysis may also be relevant for other U-based superconductors.