Transition metal doped arsenene: Promising materials for gas sensing, catalysis and spintronics

Based on first-principles calculations, we systematically investigated the stability, electronic and magnetic properties of transition metal (TM)-doped arsenene (TM = Cr, Mn, Fe, Co, Ni, and Cu) with O-2 adsorbed, and further explored the catalytic performance of TM-doped arsenene for CO oxidation. The substitutions of TM atoms induce the magnetic ground states of arsenene exception for Cu, which arises from the strong hybridizations of 3d orbitals of TM atoms and 4p orbitals of surrounding As atoms. Mn-, Co- and Ni-doped arsenenes are half metals showing potential applications in spintronics. O-2 molecule prefers to chemisorb at the TM-doped arsenene systems with larger adsorption energies than those for perfect arsenene, indicating TM-doped arsenene can be used as O-2 sensor with promoted sensitivity. It is worthy to notice that Cr-doped arsenene transforms from a diluted magnetic semiconductor to a magnetic metal owing to the adsorption of O-2. The partially occupied O( )2p and Cr 3d orbitals suggest that O-2 molecule is highly activated, which is consistent with the largest elongation of O-O bond length. The barrier of CO oxidation on Cr-doped arsenene through Langmuir-Hinshelwood (LH) mechanism is 0.72 eV, which implies that TM-doped arsenene may be promising single atom catalysts for the oxidation of CO.