DFT study of Ag-X (X = Pd, Pt, Ag) decorated (8,0) single wall carbon nanotube for spintronic applications

Abstract

The main purpose of the present article is an investigation of the electronic and magnetic properties of (8,0) single-wall carbon nanotube (CNT80) decorated with a diatomic configuration of Ag and X (X = Pd, Pt, and Ag). Density functional theory and the Grimme-D2 approach in spin polarization mode are employed. It is concluded that Ag and X are adsorbed on CNT80 in the dimer form rather than singly atomic adsorption. The spin-distinct electronic band structure and the densities of states are also calculated. The calculations show that Ag-Pd/CNT80 is a bipolar semiconductor with an energy gap of 0.27 eV for spin-up, 0.47 eV for spin-down, and 0.15 eV for spin-flip electrons. Ag-Pt/CNT80 is an anti-ferromagnetic p-type indirect semiconductor with a gap of 0.187 eV for temperatures below 188 K. After 188 K up to around 330 K, this structure converts to an indirect bipolar semiconductor, with an energy gap of 0.31 eV (0.37 eV) for the spin-up (down) channel. Adsorption of Ag dimer onto CNT80 leads to the p-type nonmagnetic semiconductor. As an application of the proposed materials, the absorption of CO as a polar molecule on the Ag-Pd/CNT80 structure is also investigated, and a proposed structure as a spintronic CO sensor is introduced.