ZrTe2/CrTe2: an epitaxial van der Waals platform for spintronics

TLDR

The rapid discovery of two‑dimensional van der Waals quantum materials has enabled heterostructures that combine topological phases, magnetism, and superconductivity. The authors aim to epitaxially grow van der Waals heterostructures with controlled interfaces to create wafer‑scale platforms for exploring fundamental properties and building proof‑of‑concept devices. Using molecular beam epitaxy, they synthesize a heterostructure that couples a 2D ferromagnet (1T‑CrTe₂) to a topological semimetal (ZrTe₂). They find that a single‑unit‑cell 1T‑CrTe₂ on ZrTe₂ is a 2D ferromagnet exhibiting a clear anomalous Hall effect; thicker 12‑unit‑cell films show anomalous Hall characteristics suggestive of real‑space Berry curvature, and ultrathin 3‑unit‑cell films enable current‑driven magnetization switching in a full vdW topological semimetal/2D ferromagnet device.

Abstract

Abstract The rapid discovery of two-dimensional (2D) van der Waals (vdW) quantum materials has led to heterostructures that integrate diverse quantum functionalities such as topological phases, magnetism, and superconductivity. In this context, the epitaxial synthesis of vdW heterostructures with well-controlled interfaces is an attractive route towards wafer-scale platforms for systematically exploring fundamental properties and fashioning proof-of-concept devices. Here, we use molecular beam epitaxy to synthesize a vdW heterostructure that interfaces two material systems of contemporary interest: a 2D ferromagnet (1T-CrTe 2 ) and a topological semimetal (ZrTe 2 ). We find that one unit-cell (u.c.) thick 1T-CrTe 2 grown epitaxially on ZrTe 2 is a 2D ferromagnet with a clear anomalous Hall effect. In thicker samples (12 u.c. thick CrTe 2 ), the anomalous Hall effect has characteristics that may arise from real-space Berry curvature. Finally, in ultrathin CrTe 2 (3 u.c. thickness), we demonstrate current-driven magnetization switching in a full vdW topological semimetal/2D ferromagnet heterostructure device.