Charge density wave observed for the first time in TaSe3 mesowires
DOI: 10.1063/1.5119367
Charge density wave observed for the first time in TaSe3 mesowires lead image
Transition metal trichalcogenides at the mesoscale have garnered attention for their exotic properties that exhibit charge density wave (CDW) and superconductivity phenomena, making them attractive for advancing field-effect transistors, flexible electronics, gas sensors and optoelectronics.
Although superconductivity in one such compound, tantalum triselenide (TaSe3), has been observed in some studies, researchers have not been able to detect CDW, even though the material’s one-dimensional metallic state should in principle become unstable enough to generate a CDW.
Now Yang et al. for the first time have observed CDW in TaSe3 mesowires with diameters between 100 and 300 nanometers. The observation was confirmed by electrical, Raman spectroscopy and magnetic susceptibility measurements.
The TaSe3 wires were grown at various diameters, ranging from 75 nanometers to 1 micrometer. The researchers discovered that the CDW transition occurs at 65 K in 300-nanometer wires and at 150 K in 110-nanometer wires.
The higher transition temperature for the thinner wire suggests that the CDW is enhanced by reducing the diameter. However, further decreasing the diameter to 75 nanometers increased the insulating properties, turning the wire into a semiconductor.
Typically, TaSe3 mesowires are produced on bulk single crystals or mechanically exfoliated from bulk crystals. For this study, the researchers used a one-step process based on the direct reaction of the Ta and Se powders that expedited their findings by speeding up the growth process and more efficiently producing different size wires.
The method itself could contribute to the enhancement of CDW in the TaSe3 wires by reconstructing the Fermi surface of the material during the growth process, which would affect the electronic structures of the material. The researchers plan to explore this possibility in more detail.
Source: “Observation of charge density wave transition in TaSe3 mesowires,” by J. Yang, Y. Q. Wang, R. R. Zhang, L. Ma, W. Liu, Z. Qu, L. Zhang, S. L. Zhang, W. Tong, L. Pi, W. K. Zhu, and C. J. Zhang, Applied Physics Letters (2019). The article can be accessed at https://doi.org/10.1063/1.5099110 .
