  We demonstrate locally coherent heteroepitaxial growth of silicon carbide
(SiC) on diamond, a result contrary to current understanding of heterojunctions
as the lattice mismatch exceeds $20\%$. High-resolution transmission electron
microscopy (HRTEM) confirms the quality and atomic structure near the
interface. Guided by molecular dynamics simulations, a theoretical model is
proposed for the interface wherein the large lattice strain is alleviated via
point dislocations in a two-dimensional plane without forming extended defects
in three dimensions. The possibility of realising heterojunctions of
technologically important materials such as SiC with diamond offers promising
pathways for thermal management of high power electronics. At a fundamental
level, the study redefines our understanding of heterostructure formation with
large lattice mismatch.
