Growth of bilayer MoTe2 single crystals with strong non-linear Hall effect

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.

Electrostatic shielding effects and binding energy shifts and topological phases of bilayer molybdenum chalcogenides

“…The calculated results show that MoTe 2 has topological edge states, which is consistent with the observed topology phases of bilayer MoTe 2 in experiments [19] …”

“…The calculated results show that MoTe 2 has topological edge states, which is consistent with the observed topology phases of bilayer MoTe 2 in experiments. [19] In order to study the process of topological phase transition, we use the magic cube matrix to obtain the transition of edge states. We use the 4th order magic cube matrix to operate on the BBH Hamiltonian:…”

Chemical Vapor Deposition Growth of 2D Ferroelectric Materials for Device Applications

“…Currently, several classes of monolayer or few-layer van der Waals (vdW) layered ferroelectric materials have been theoretically predicted, but a few 2D materials including SnTe, 1T′-WTe 2 , d1T-MoTe 2 , In 2 Se 3 , and CuInP 2 S 6 have been experimentally observed. [7,[22][23][24] Table 1 lists the critical thickness and the corresponding polarization values of representative 2D ferroelectric materials. [25][26][27][28][29][30][31] More recently, some 2D materials have been found to possess non-intrinsic ferroelectricity with sliding ferroelectric mechanisms, such as hBN, MoS 2 , etc.…”

Promoted Electronic Coupling of Acoustic Phonon Modes in Doped Semimetallic MoTe2

“…Also, the charge doping can modulate structural stability and induce phase transitions for layered MoTe 2 . Besides that, there was a recent breakthrough achieved for synthesizing centimeter-sized high-quality bilayer and trilayer 1T′-MoTe 2 films successfully . So far, it is still unclear how electronic doping alters the atomic vibrations and the momentum-resolved electron–phonon coupling for the phonons.…”