Pressure induced semiconductor-metallic transition of selenium nanoribbons generated by laser ablation in liquids

Single crystalline Selenium (Se) nanoribbons with large length-diameter ratio was catalytically synthesized by laser ablation in liquids. In this study, the unique growth, pressure-dependent phase evolution and superconducting transition of Se nanoribbons are systematically investigated. Importantly, we first found that the semiconductor-metal transition pressure of such Se nanoribbons located at 11.1 GPa at room temperature, which was extremely close to the theoretically predicated value of 11.16 GPa of hexagonal Se. The structure evolution of Se nanoribbons revealed via in situ Raman spectrum indicated three subsequent phase transition stages. The temperature dependence of resistance measurements revealed the occurrence of superconducting state of monoclinic Se at 11.8 GPa, which is markedly lower than reported pressures to date. The phase transition barrier attenuation originating from the volumetric contraction of Se lattice is assumed to offset the influences of temperature and surface energy in low-dimensional Se nanoribbons with large length-diameter ratios, resulting in a transition pressure approaching the predicted value.