Higgs boson masses and mixings in the complex MSSM with two-loop top-Yukawa-coupling corrections

Results for the leading two-loop corrections of $\mathcal{O}{\left(\alpha_t^2\right)}$ from the Yukawa sector to the Higgs-boson mass spectrum of the MSSM with complex parameters are presented, with details of the analytical calculation performed in the Feynman-diagrammatic approach using a mixed $\left.\text{on-shell}\middle/\,\overline{\text{DR}}\right.$ scheme that can be directly matched onto the higher-order terms in the code ${\tt FeynHiggs}$. Numerical results are shown for the masses and mixing effects in the neutral Higgs-boson sector and their variation with the phases of the complex parameters. Furthermore, the analytical expressions of the two-loop self-energies and the required renormalization constants are recorded. The new results can consistently be implemented in ${\tt FeynHiggs}$.