Recently, the research group led by Prof. Xiang Yuan at the State Key Laboratory of Precision Spectroscopy, East China Normal University, proposed and achieved the synthesis of a new 2D ternary compound transition metal chalcogenide, Ta3VSe8. The related results were published online in Micromachines under the title "Synthesis and Characterization of 2D Ternary Compound TMD Materials Ta3VSe8."
In the exploration of new dimensional topological physics, two-dimensional van der Waals materials, especially transition metal chalcogenides with rich properties, present a promising research platform. Transition metal chalcogenides are one of the widely studied material families in the field of materials science. They exhibit a van der Waals layered structure similar to graphite, where transition metal atom layers are typically sandwiched between layers of chalcogen elements, allowing for easy mechanical exfoliation. Transition metal chalcogenides possess a range of unique properties, including adjustable band gaps, light-matter interactions, spin-orbit coupling, and valley-selective responses. Due to these unique physical properties, transition metal chalcogenides have promising applications in various fields, including electronics, optoelectronics, thermoelectrics, nano-mechanics, and valleytronics.
Previous research has mainly focused on binary transition metal chalcogenides, while studies on ternary transition metal chalcogenides (which contain two metal elements) are relatively scarce. The introduction of new ternary transition metal chalcogenides may expand the horizons of existing research, as they provide additional parameters to modulate the properties of samples, and altering the elemental ratios can influence their physical properties, thereby facilitating the exploration of two-dimensional topological properties and topological quasi-particles. Moreover, ternary transition metal chalcogenides containing magnetic elements may naturally polarize the valleys of the material itself, offering possibilities for new dimensional topological research based on valleytronics.
In this study, the researchers obtained single crystals of Ta3VSe8 through chemical vapor transport in a dual-zone furnace. The sizes of the crystals range from approximately 9 to 25 mm2, and their macroscopic plate-like and microscopic step-like features indicate a van der Waals layered structure similar to that of graphite. X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) analyses confirmed the crystal quality and the uniformity of elemental distribution. Furthermore, Raman spectroscopy at different temperatures and studies on electrical transport from liquid helium temperature to room temperature demonstrated the stability of phonons and the rapidly suppressed positive magnetoresistance phenomenon with increasing temperature.
This work was independently completed by Prof. Yuan's group at East China Normal University. The project was supported by the National Key R&D Program of China and the National Natural Science Foundation of China. The paper identifies Prof. Yuan as the corresponding author, with master's students Yuanji Ma (2020 cohort) and Yuhan Du (2021 cohort) as co-first authors.
More information: https://www.mdpi.com/2072-666X/15/5/591
