Study On The Structure,Elastic Properties And Curie Temperature Of Two-dimensional Magnetic Materials MnXY(X,Y=S,Se,Te,X?Y)

Since the successful preparation of graphene,two-dimensional materials based on their unique properties and superior properties have attracted extensive attention in many scientific and technological fields.The research on two-dimensional magnetic materials is the key to the optoelectronic devices and topological materials.In this paper,the structural,elastic properties and Curie temperature of two-dimensional intrinsic magnetic material Mn XY(X,Y = S,Se,Te,X ? Y)are studied by using the density functional theory with first principles calculations.In this paper,the first-principles method based on density functional theory is used to systematically study the two-dimensional intrinsic magnetic material Mn XY(X,Y=S,Se,Te,X?Y),including its crystal structure,electronic structure,elastic properties and Curie temperature.We have studied the structure,electron and elastic properties of two-dimensional magnetic material Mn XY(X,Y=S,Se,Te,X?Y)by GGA-PBE method.The main conclusions are as follows:(1)The ground state of two-dimensional magnetic material Mn XY(X,Y=S,Se,Te,X?Y)is dynamically stable.(2)The two-dimensional magnetic material Mn XY(X,Y=S,Se,Te,X?Y)has the properties of ferromagnetic metal.In Mn STe,it can be clearly seen that the spin up band structure is semiconducting,while the spin down band structure is metallic,which means that the monolayer of Mn STe is a semimetal.When U is added to the spin-polarized energy band,it is observed that both the spin up and spin down energy bands of Mn XY(X,Y=S,Se,Te,X?Y)are pass through by the Fermi level,indicating that the above three materials have ferromagnetic metal properties.When SOC is considered,the spin-orbit interaction causes the energy band split at the Dirac cone,indicating that the SOC splits the energy band near the Fermi level in the form of energy transfer and the band gap opening.(3)The layer modulus and Young's modulus of two-dimensional magnetic material Mn XY(X,Y=S,Se,Te,X?Y)are far less than those of graphene and other two-dimension al materials.Therefore,it can be concluded that two-dimensional Mn XY(X,Y=S,Se,Te,X?Y)material has low hardness and good flexibility,which makes it can be used to manufacture optoelectronic or electronic devices with a large strain range.We also studied the magnetic ground state,magnetic anisotropy energy and Curie temperature of Mn XY(X,Y=S,Se,Te,X?Y)by GGA+U,GGA+SOC+U and Monte Carlo simulation,and obtained the following conclusions:(1)The ground state of two-dimensional magnetic material Mn XY(X,Y=S,Se,Te,X?Y)is a ferromagnetic state.(2)The magnetic anisotropy energies of Mn XY(X,Y=S,Se,Te,X?Y)are calculated to be-18.53 K(Mn STe),-2.06 K(Mn Se Te)and-0.12 K(Mn SSe),respectively,consider-ing the spin-orbit coupling effect.(3)The Curie temperature of Mn XY(X,Y=S,Se,Te,X?Y)was obtained by GGA+S OC+U algorithm,and the Curie temperature of the three were 58 K(Mn STe),45 K(Mn Se Te)and 70 K(Mn SSe),respectively,whose magnitude might be related to the relative atomic mass.