Enhancement of carrier transport characteristic in the Sb₂Se₂Te topological insulators by N₂ adsorption

The carrier transport characteristics of Sb₂Se₂Te topological insulators were investigated, after exposure to different levels of nitrogen gas. The magnetoresistance (MR) slope for the Sb₂Se₂Te crystal increased by approximately 100% at 10 K after 2-days of exposure. The Shubnikov-de Haas (SdH) oscillation amplitude increased by 30% while oscillation frequencies remained the same. MR slopes and the mobilities had the same dependency on temperature over a wide temperature range. All measured data conformed to a linear correlation between MR slope and mobility, supporting our hypothesis that the MR increase and the SdH oscillation enhancement might be caused by mobility enhancement induced by adsorbed N₂ molecular.