First-principles Study On The Electronic And Magnetic Properties Of Diamond Nanothread By Doping

With the rapid development of today's information technology,people have higher and higher requirements for the size and performance of information devices,and have gradually entered the era of nano devices!Due to the diverse structures of nanomaterials,their unique structure and excellent physical and chemical properties have attracted widespread attention from researchers.By adjusting the structure of nanomaterials,the properties of materials can be changed to a great extent,so as to obtain material properties that meet the needs of specific applications.In particular,through the theoretical design and performance simulation of nanomaterials,the key physical factors affecting the performance of materials can be found,so as to provide theoretical guidance for the optimization of nanomaterial properties and its application in electronic devices.In this paper,based on the first-principles calculations of density functional theory,the electronic structure characteristics and doping modulation of diamond nanothreads are mainly studied.The main research contents and conclusions are as follows:(1)The electronic structure characteristics of one-dimensional diamond nanothreads doped with metal atoms aluminum(Al)and gallium(Ga)were studied,and it was found that doping Al and Ga can reduce the band gap of diamond nanothreads.Compared with doped isolated metal atoms,pure diamond nanothread systems are more easily passivated by hydrogen atoms,and the hydrogenated Al and Ga doped systems can produce magnetic properties.When polar molecules carbon monoxide(CO)and nitrogen monoxide(NO)are adsorbed on diamond nanothreads doped with metal atoms,the system exotherms,and the adsorption energy of NO molecules is greater than that of CO molecules,with the band gap value ranges from 0.40 to 1.92e V.The adsorption of CO molecules will not change the non-magnetic properties of diamond nanothreads,while the adsorption of NO molecules will introduce magnetism into the diamond nanothread system.(2)The effects of transition metal atom doping on the electronic and magnetic properties of diamond nanothreads were investigated.The calculation results show that,except for the impurity states near the Fermi level,the transition metal atom doping has not changed the spin polarization state characteristics of the diamond nanothread system band gap.For diamond nanothread systems doped with scandium(Sc),vanadium(V),chromium(Cr),manganese(Mn),and cobalt(Co),the characteristics of spin-polarized semiconductors have been achieved.The change of magnetic moment is in the range of1.00?_Bto 3.00?_B,where the largest magnetic moment is doped by Mn atoms,the magnetic moment is 3.00?_B;Diamond nanothread systems doped with iron(Fe)atoms exhibit metallic state characteristics with a magnetic moment of 2.58?_B;Titanium(Ti)and nickel(Ni)doped diamond nanothread systems have semiconductor properties and are not magnetic.