A New One-dimensional Quantum Material - Ta$_{2}$Pd$_{3}$Se$_{8}$ Atomic Chain

Since the discovery of carbon nanotube, there has been a persistent effort to search for other one dimensional (1D) quantum systems. However, only a few examples have been found. We report a new 1D example - semiconducting Ta$_{2}$Pd$_{3}$Se$_{8}$. We demonstrate that the Ta$_{2}$Pd$_{3}$Se$_{8}$ nanowire as thin as 1.3nm can be easily obtained by applying simple mechanical exfoliation from its bulk counterpart. High resolution TEM shows an intrinsic 1D chain-like crystalline morphology on these nano wires, indicating weak bonding between these atomic chains. Theoretical calculation shows a direct bandgap structure, which evolves from 0.53eV in the bulk to 1.04eV in single atomic chain. The field effect transistor based on Ta$_{2}$Pd$_{3}$Se$_{8}$ nanowire achieved a promising performance with 10$^{4\, }$On/Off ratio and 80 cm$^{2}$V$^{-1}$s$^{-1}$ mobility. Low temperature transport study reflects two different mechanisms, variable range hopping and thermal activation, which dominate the transport properties at different temperature regimes. Ta$_{2}$Pd$_{3}$Se$_{8}$ nanowire provides an intrinsic 1D material system for the study low dimensional condensed matter physics.