| Due to its excellent photoelectric property and wide band gap,two-dimensional silicon carbide(SiC)has unique advantages in the designed low-dimension materials,which is a well artificial tunable spin two-dimensional material non-magnetic extended substrate.The local spin modulation of two-dimensional SiC can achieve artificial tunable of magnetism and local spin of two-dimensional SiC at atomic level.For the modulation of two-dimensional SiC local spin,most of them focus on the local spin induced by 3d excessive metal doping,but for 4 d transition metal doped tunable local spin is less,this article adopts the way of doped Mo(N)atoms,the two-dimensional SiC magnetic control,analyze the regulation mechanism of local spin,enriched the Mo doping system(N)co-doped theory under the condition of the data.Nonequivalent sites of intrinsic two-dimensional SiC provide many options for artificial local spin regulation.In this paper,the magnetic properties of two dimensional SiC materials are doped by Mo atom with different selection positions.As for the selective doping of Mo atom at different two-dimensional SiC sites,the study found that the Si site,interstitial site and C site of Mo atom presented the phenomenon of spin polarization in the system,which are all transformed from semiconductor to semi-metal system.Further,it is clear the magnetic and local spin changes of the system are mainly induced by doping Mo.Furthermore,magnetic Mo position doped two-dimensional SiC reveals different spin mechanisms.When Mo is substituted at doping Si site,the magnetic moment of the system is 2.000?B,and the spin-up electron band structure cross the Fermi level,forming a small polaron and two kinds of external and internal Wely points above and below the Fermi level.When Mo substituted at hole,the magnetic moment of the system becomes 2.003?B.Similarly,the spin-up electron still across the Fermi energy level,but the small polaron disappears,showing a certain degree of delocalization.When Mo substituted at C site,the magnetic moment of the system became 1.997?B,and the spin-down electron across the Fermi level,which shows the characteristic of spin-down electron conductivity.The Fermi surface of three spin two-dimensional SiC shows different electron motion states,and the spin texture exhibit anisotropy of magnetic in space.When Mo doped magnetic 2D SiC,all the systems are half metallic,therefore it is considered to use N passivation of the metallic property,turn it into a magnetic semiconductor.In the spin control process,Mo doped polar two-dimensional SiC at Si site,which the spin-up electron on Fermi surface has excellent spin control performance.In the magnetic material which Mo substituted Si,the band gap of the substrate material is modulation by the addition of N.The results show the selective doping of N near Mo,where Mo replaces Si doped magnetic 2-D SiC,can transform semi-metallic properties into semiconductors with a band gap.For the magnetic modulation with co-doped N,the local spin state of magnetic 2-D SiC can be fine-tuned at different sites of N.The density of state the highest occupied orbital and the lowest non-occupied orbital showed the transmission mechanism of different systems has the transformation between others.The addition of N induces different electron spin transport mechanisms around Mo,resulting in different local spin states of the system and the formation of weak local spin around N.The exchange between electrons forms the anisotropy of the system.The research results of this paper provide abundant theoretical data and design scheme for the manual design of two-dimensional electronic devices... |
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