Growth of bilayer MoTe2 single crystals with strong non-linear Hall effect
Teng Ma, Hao Chen, Kunihiro Yananose, Xin Zhou, Lin Wang, Runlai Li, Ziyu Zhu, Zhenyue Wu, Qing‐Hua Xu, Jaejun Yu, Cheng‐Wei Qiu, Alessandro Stroppa, Kian Ping Loh
Abstract
Abstract The reduced symmetry in strong spin-orbit coupling materials such as transition metal ditellurides (TMDTs) gives rise to non-trivial topology, unique spin texture, and large charge-to-spin conversion efficiencies. Bilayer TMDTs are non-centrosymmetric and have unique topological properties compared to monolayer or trilayer, but a controllable way to prepare bilayer MoTe 2 crystal has not been achieved to date. Herein, we achieve the layer-by-layer growth of large-area bilayer and trilayer 1T′ MoTe 2 single crystals and centimetre-scale films by a two-stage chemical vapor deposition process. The as-grown bilayer MoTe 2 shows out-of-plane ferroelectric polarization, whereas the monolayer and trilayer crystals are non-polar. In addition, we observed large in-plane nonlinear Hall (NLH) effect for the bilayer and trilayer T d phase MoTe 2 under time reversal-symmetric conditions, while these vanish for thicker layers. For a fixed input current, bilayer T d MoTe 2 produces the largest second harmonic output voltage among the thicker crystals tested. Our work therefore highlights the importance of thickness-dependent Berry curvature effects in TMDTs that are underscored by the ability to grow thickness-precise layers.