Wafer-scale epitaxial growth of the thickness-controllable van der Waals ferromagnet CrTe2 for reliable magnetic memory applications

TL;DR

This paper reports the successful wafer-scale epitaxial growth of a 2D ferromagnetic material, CrTe2, with controllable thickness, enabling reliable magnetic memory devices with reduced switching power.

Contribution

It introduces a method for epitaxial growth of single-crystalline CrTe2 films on large wafers, allowing precise thickness control and improved device performance.

Findings

Uniform layer-by-layer growth across 2-inch wafers

Tunable anomalous Hall response via Coulomb interaction

54% reduction in switching power for spin-orbit torque devices

Abstract

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.