Synthesis of Ultrathin Metallic MTe₂ (M = V, Nb, Ta) Single‐Crystalline Nanoplates

Abstract

Two-dimensional materials with intrinsic magnetism have recently drawn intense interest for both the fundamental studies and potential technological applications. However, the studies to date have been largely limited to mechanically exfoliated materials. Herein, an atmospheric pressure chemical vapor deposition route to ultrathin group VB metal telluride MTe (M = V, Nb, Ta) nanoplates with thickness as thin as 3 nm is reported. It is shown that the resulting nanoplates can be systematically evolved from mostly thicker hexagonal domains to thinner triangular domains with an increasing flow rate of the carrier gas. X-ray diffraction and transmission electron microscopy studies reveal MTe (M = V, Nb, Ta) nanoplates are high-quality single crystals. High-resolution scanning transmission electron microscope imaging reveals the VTe and NbTe nanoplates adopt the hexagonal 1T phase and the TaTe nanoplates show a monoclinic distorted 1T phase. Electronic transport studies show that MTe single crystals exhibit metallic behavior. Magnetic measurements show that VTe and NbTe exhibit ferromagnetism and TaTe shows paramagnetic behavior. The preparation of ultrathin few-layered MTe nanoplates will open up exciting opportunities for the burgeoning field of spintronics, sensors, and magneto-optoelectronics.

Polymorphic Spin, Charge, and Lattice Waves in Vanadium Ditelluride

“…The bond length difference between types 1 and 2 is limited to 0.1 Å, but the Laue diffraction patterns precisely reveal that the unit cell of the type 2 CDW is three times larger than that of type 1. Overall, the new phase, type 2 CDW, has an additional lattice distortion along the b-axis that has not been observed in previous reports on CDWs in VTe 2 ; [15][16][17][18][19]21] the intervanadium distance of 3.61 Å along the b-axis is split into 3.52 and 3.65 Å, as shown in the right panel of Figure 2a.…”

“…Vanadium ditelluride (VTe 2 ), a group 5 TMD, provides a platform for investigating the unexplored correlation between CDW and other quantum states, particularly those with magnetism 15–19. The moderate CDW transition temperature of bulk VTe 2 ( T C ≈ 480 K) compared with other CDW materials, such as VSe 2 ,20 allows a thorough study of the magnetism in its CDW phase.…”

“…The moderate CDW transition temperature of bulk VTe 2 ( T C ≈ 480 K) compared with other CDW materials, such as VSe 2 ,20 allows a thorough study of the magnetism in its CDW phase. Since the late 1950s, both CDW and magnetic orderings have been separately reported in VTe 2 of various thicknesses;15–19,21 in the former studies, however, the powder and thin film‐based VTe 2 materials showed conflicting features regarding their lattice structure at room temperature 19,20,22. Recent studies of thin VTe 2 films show that the interlayer interaction plays a role for the structural changes 18,23,24.…”

“…Vanadium ditelluride (VTe 2 ), a group 5 TMD, provides a platform for investigating the unexplored correlation between CDW and other quantum states, particularly those with magnetism. [15][16][17][18][19] The moderate CDW transition temperature of bulk VTe 2 (T C ≈ 480 K) compared with other CDW materials, such as VSe 2 , [20] allows a thorough study of the magnetism in its CDW phase. Since the late 1950s, both CDW and magnetic orderings have been separately reported in VTe 2 of various thicknesses; [15][16][17][18][19]21] in the former studies, however, the powder and thin film-based VTe 2 materials showed conflicting features regarding their lattice structure at room temperature.…”

2D Crystal–Based Fibers: Status and Challenges

“…Chalcogenide X forms chemical bonds, and M provides four electrons to form oxidized states. The valences of M and X are +4 and −2, respectively . The paired electrons of chalcogenide X are located at the outer edge of X–M–X layer, which ensures that no unbounded electrons exist at the outer edge of the layer, leading to a stable MX 2 layer .…”