  The intrinsic antiferromagnetic (AFM) interlayer coupling in two-dimensional
magnetic topological insulator MnBi$_2$Te$_4$ places a restriction on realizing
stable quantum anomalous Hall effect (QAHE) [Y. Deng et al., Science 367, 895
(2020)]. Through density functional theory calculations, we demonstrate the
possibility of tuning the AFM coupling to the ferromagnetic coupling in
MnBi$_2$Te$_4$ films by alloying about 50% V with Mn. As a result, QAHE can be
achieved without alternation with the even or odd septuple layers. This
provides a practical strategy to get robust QAHE in ultrathin MnBi$_2$Te$_4$
films, rendering them attractive for technological innovations.
