The Magnetic Control Of Transition Metal Doped 2D Materials Through Chemical Decoration

With the continuous development of the level of integrated circuit, the traditional technology of silicon electronics development has reached a plateau. In order to adapt to the development of the information age, it is necessary for us to find new material to go beyond the traditional silicon electronic devices. Since graphene was successfully prepared in 2004, two dimensional materials have attracted extensive attention. Hexagonal boron nitride, molybdenum disulfide, and other wo-dimensional materials have also been prepared successfully. Two dimensional materials have excellent and unique quantum effect in small scale, so it is regarded as the excellent material for the preparation of micro nano electronic devices. Transition metal doping can effectively control the magnetic and electronic properties of 2d materials. The magnetic and electronic properties of doped systems is very sensitive to their crystalline environment. This article adopts the method of the first principles to study the effects of chemical decoration on magnetic properties of transition metal embedded two-dimensional, and obtain the following results:（1）Magnetic control of transition metal doped graphene by H atomic chemical modification. We analyzed the effect of Hubbard U on the magnetic properties and electronic structure of transition metal doped graphene system. The electronic properties of transition metals embedded in graphene are very sensitive to the local Coulomb potential. We obtained the Hubbard U of doped systems under self-consistent calculation, through the linear response method. DFT+U method is applied to study the effects of H atom chemical modification on doping system. We found that the H chemical decoration can effectively modified the magnetism of doped system, can make the spin state of Co@SV system become a spin switch from “spin on” to “spin off”. We analyzed the mechanism of chemical decoration by the crystal field splitting and exchange splitting. The H chemical decoration can change the distribution of the d state electrons of 3d transition metal atom, which can induce the uniformed distribution of electrons in majority spin channel and minority spin channel, thus effectively control the magnetic characteristics of system.（2） Magnetic Control of Single Transition Metal Doped MoS₂ Through H/F Chemical Decoration. We find that H/F can effectively control the magnetic and electronic structures of transition metals（TM=Mn, Fe and Co） doped in MoS₂. We found that the magnetic moment of TM doped in the monolayer MoS₂ increase 1μB, while the F chemical decoration can decrease the magnetic moment of 1μB. The electronic structures system of H-Mn-MoS₂, H-Co-MoS₂, F-Fe-MoS₂ and F-Co-MoS₂ is semi-half-metallic, and the spin polarization is found to be 100% at Fermi level. For the H-Fe-MoS₂ system, the spin polarization is found to be 100% at Highest Occupied Molecular（HOMO）, the systems turns out to be spin-selected half semiconductor. For the system of F-Mn-MoS₂, the ground spin state will be from "spin ON" to "spin OFF". For the system of F-Co-MoS₂, which indicate the system is a spin switch. We analyzed the mechanism of chemical adsorption by means of crystal field splitting and molecular bonding. We found out that the anti-bonding nature produces the d states of TM atom directly coupled with the s state of H atom take same spin state. Such bonding nature will induce the enhancement of the magnetic moment of gapH chemical decorated systems and the bonding nature produces the d states of TM atom directly coupled with the p state of F atom take same spin state. Such bonding nature will induce the enhancement of the magnetic moment of F chemical decorated systems. Our results may open a new route to realize the application of spintronics and quantum information.