  To harness the intriguing properties of two-dimensional van der Waals (vdW)
ferromagnets (FMs) for versatile applications, the key challenge lies in the
reliable material synthesis for scalable device production. Here, we
demonstrate the epitaxial growth of single-crystalline 1T-CrTe2 thin films on
2-inch sapphire substrates. Benefiting from the uniform surface energy of the
dangling bond-free Al2O3(0001) surface, the layer-by-layer vdW growth mode is
observed right from the initial growth stage, which warrants precise control of
the sample thickness and atomically smooth surface morphology across the entire
wafer. Moreover, the presence of the Coulomb interaction at the CrTe2/Al2O3
interface serves as an effective tuning parameter to tailor the anomalous Hall
response, and the structural optimization of the CrTe2-based spin-orbit torque
device leads to a substantial switching power reduction by 54%. Our results may
lay out a general framework for the design of energy-efficient spintronics
based on configurable vdW FMs.
