A Review of the Characteristics, Synthesis, and Thermodynamics of Type-II Weyl Semimetal WTe2

Abstract

WTe2 as a candidate of transition metal dichalcogenides (TMDs) exhibits many excellent properties, such as non-saturable large magnetoresistance (MR). Firstly, the crystal structure and characteristics of WTe2 are introduced, followed by a summary of the synthesis methods. Its thermodynamic properties are highlighted due to the insufficient research. Finally, a comprehensive analysis and discussion are introduced to interpret the advantages, challenges, and future prospects. Some results are shown as follows. (1) The chiral anomaly, pressure-induced conductivity, and non-saturable large MR are all unique properties of WTe2 that attract wide attention, but it is also a promising thermoelectric material that holds anisotropic ultra-low thermal conductivity (0.46 W·m−1·K−1). WTe2 is expected to have the lowest thermal conductivity, owing to the heavy atom mass and low Debye temperature. (2) The synthesis methods influence the properties significantly. Although large-scale few-layer WTe2 in high quality can be obtained by many methods, the preparation has not yet been industrialized, which limits its applications. (3) The thermodynamic properties of WTe2 are influenced by temperature, scale, and lattice orientations. However, the in-plane anisotropy cannot be observed in the experiment, as the intrinsic property is suppressed by defects and boundary scattering. Overall, this work provides an opportunity to develop the applications of WTe2.

Controlled Synthesis of MoxW1–xTe2 Atomic Layers with Emergent Quantum States

“…But according to the intrinsic phase structure of MoTe2 and WTe2, 22,[31][32][33] and previous research in MoxW1-xTe2, [17][18][19] it has reached a consensus that a 1T′ phase is dominated in Mo-rich sample and 1Td phase dominated in W-rich sample, while a phase mixing behavior is presented in most composition ratios of MoxW1-xTe2 alloys. Therefore, the Mo-rich Mo0.8W0.2Te2 and W-rich Mo0.2W0.8Te2 samples we studied can be reasonably regarded as 1T′ and 1Td phase respectively.…”

Tungsten Ditelluride: Synthesis, Structure, and Magnetoresistance Property

“…High-resolution TEM shows a orthorhombic atomic lattice of alternating bright and dark regular spots with a lattice spacing of 0.35 nm (Figure 5c), which is consistent with the structure of orthorhombic WTe 2 and confirmed the WTe 2 of highly crystalline properties (Figure 5d). [31]…”

Positive Magnetoresistance and Chiral Anomaly in Exfoliated Type-II Weyl Semimetal Td-WTe2

“…The presence of tilted Weyl cones and of low energy excitations violating the Lorentz invariance in the vicinity of the Weyl points were predicted for the electronic band structure of WTe 2 , a transition metal dichalcogenide (TMDC) semimetal with layered van der Waals structure [21,22]. In addition to the presence of the Fermi arc at the Fermi surface [23][24][25], anisotropic transport properties including extreme transverse magnetoresistance and the anisotropic ABJ anomaly, are reported for both bulk and few layers WTe 2 flakes [15,[26][27][28][29][30][31][32][33][34][35][36].…”