Searches for new physics in the Higgs sector at ATLAS

The discovery of the Higgs boson with a mass of 125 GeV confirmed the mass generation mechanism via spontaneous electroweak symmetry breaking and completed the particle content predicted by the Standard Model (SM). Even though this model is well established and consistent with many experimental measurements, it is not capable of solely explaining some observations. Many extensions of the SM introduce additional scalar fields to account for the electroweak symmetry breaking and thereby extra Higgs-like bosons, which can be either neutral or charged. Some models also introduce exotic production modes and/or decays of the SM-like Higgs boson. This talk presents recent searches for additional low- or high-mass Higgs bosons using LHC collision data at 13 TeV collected by the ATLAS experiment in Run 2.