Single Top-Quark Production Cross Section Using the ATLAS Detector at the LHC

Recent measurements of the production of single top quarks in proton--proton collisions at centre-of-mass energies of $\sqrt{s}=7\,\mathrm{TeV}$, $8\,\mathrm{TeV}$ and $13\,\mathrm{TeV}$ with the ATLAS detector at the LHC are presented. Four measurements of the production cross sections for single top quarks via the $s$- and $t$-channel exchange of a $W$ boson as well as in association with a \Wboson{} are discussed. The results are compared to state-of-the-art theoretical calculations, and used to extract the value of the CKM matrix element $V_{tb}$. Recently found evidence for the production of single top quarks in the $s$-channel at $8\,\mathrm{TeV}$ is presented. Finally, the determination of anomalous couplings at the $W\!-\!t\!-\!b$ vertex from an analysis of top-quark decays is shown.