Intrinsic and tunable quantum anomalous Hall effect and magnetic topological phases in XYBi2Te5

By first-principles calculations, we study the magnetic and topological properties of $\mathit{XY}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{5}$-family $(X, Y=\mathrm{Mn},\mathrm{Ni},\mathrm{V},\mathrm{Eu})$ compounds. The strongly coupled double magnetic atom-layers can significantly enhance the magnetic ordering temperature while keeping the topologically nontrivial properties. Particularly, ${\mathrm{NiVBi}}_{2}{\mathrm{Te}}_{5}$ is found to be a magnetic Weyl semimetal in bulk and a Chern insulator in thin film with both the Curie temperature ($\ensuremath{\sim}150$ K) and full gap well above 77 K. ${\mathrm{Ni}}_{2}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{5}, {\mathrm{MnNiBi}}_{2}{\mathrm{Te}}_{5}, {\mathrm{NiVBi}}_{2}{\mathrm{Te}}_{5}$, and ${\mathrm{NiEuBi}}_{2}{\mathrm{Te}}_{5}$ exhibit intrinsic dynamic axion state. Among them, ${\mathrm{MnNiBi}}_{2}{\mathrm{Te}}_{5}$ has a N\'eel temperature over 200 K and ${\mathrm{Ni}}_{2}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{5}$ even demonstrates antiferromagnetic order above room temperature. These results indicate an approach to realize high-temperature quantum anomalous Hall effect and other topological quantum effects for practical applications.