Computational Study of 4d transition metals doped bismuthene for spintronics

Two-dimensional (2D) materials have significant attention because of their amazing physicochemical and optoelectronic properties; have been used widely for application in various aspects. The first search was graphene, successively its correspondents, such as silicene, BN, transition metal dichalcogenide/oxides (TMDs/TMOs) are registered. But, 2D materials have more or less fault, for example, zero band-gap of graphene, insulator of BN and low carrier mobility of some TMD which considerably constrains its application in the field of spintronic devices. Hence the great effort being dedicated towards the exploitation of such new 2D materials, which possess reasonable band-gap, high carrier mobility and others interesting electronic properties are still an important challenge.

In order to search new materials which can be used for spintronic devices, she chooses 2D-bismuthene (Bi) to investigate its electronic and magnetic properties after doping of 4d transition metals (TMs), which are Y, Zr, Nb, Mo, Tc and Ru by using first principle calculations based on the density fuctional theory (DFT). As bismuthene is a semiconductor with large band gap. First, I optimize the structure of pure bismuthene supercell of 32 atoms then doped single atom in Bi slab of atoms and check its electronic properties, the results suggest that after doping the band gap reduces and the behavior of Bi changes to half matel for Tc,R, Nb doping cases. To check its magnetic behavior, she doped two atoms which shows that Y and Zr doped systems are nonmagnetic.

My study showed the  one Zr, Nb, Tc and Ru doped Bi shows magnetic half-metallic behavior. The doping of Mo and Y atoms exhibit magnetic and nonmagnetic semiconductor char-acter respectively. The total magnetic moments are mainly from impurity atoms, due to the strong orbital hybridization mechanism of (TM-d) and 6p orbital of Bi. Moreover, when two doping atoms are proposed, the 2Nb–S-FM, 2Nb–S-AFM and 2Nb–B-FM have half metallic character, the 2Y–Bi and 2Mo–Bi and 2Zr–B-AFM systems show semiconductor characteristics, the 2Tc-B-AFM, 2Ru–S-AFM, 2Zr–S-FM, 2Tc-S-AFM and 2Zr–S-AFM systems doped in Bi show metallic behavior. The one and two atoms doping systems of Mo–Bi except 2Mo–B-AFM show DMS properties. In 2Ru–B-FM case the spin-gapless semiconductor behavior has been observed. The 2Tc-S-Bi and 2Mo–S–Bi appears FM coupling, while 2Tc-B-Bi and 2Mo–B–Bi systems display AFM state. The 2Y–Bi and 2Zr–Bi systems are nonmagnetic.

Our investigations reveal that Y, Zr, Nb, Mo, Tc and Ru doping can commendably modify the electronic and magnetic properties for bismuthene system, due to different TM atom. We expect that our current investigation would arouse more experimental research of 4 d-TM doped b-Bi like a favorable applicant for the applications in electronic as well as spintronic materials.