Search

Recently. the exploration of two-dimensional (2D) ferromagnetic materials has become a hot topic in the field of spintronic devices. In this work, Fe3 As, a new two-dimensional material, with Curie temperature ( Tc) of 300 K ( reach room temperature), was designed by means of spin-polarized density generalization theory calculations. The predicted 2D Fe3As has strong in-plane Fe--Fe coupling with large magnetic anisotropy energy (MAE) of approximately 366. 7 μeV, which contributes to maintain a long-range ferromagnetic order. The energy band of Fe3 As has both flat band and Dirac point features. The position of the flat band is positively related to the strength of the magnetic coupling. Furthermore, Tc increases progressively as the distance between the flat band and the Fermi surface continues to decrease under the effect of the biaxial strain. Therefore, Fe3As monolayer is considered to be a promising candidate for 2D room-temperature spintronics devices. [ABSTRACT FROM AUTHOR]

Since the discovery of graphene, various two-dimensional materials with novel properties have attracted more and more attention. Janus two-dimensional materials have asymmetric surface properties. These special structures often have peculiar electrical, magnetic and optical properties, which have become a research hotspot in the field of material science in recent years. In this paper, the structures of Janus two-dimensional materials CrXX'(X/X'= S,Se,Te)(CrSSe, CrSTe, CrSeTe) were built, their electronic, magnetic, optical properties were studied, and the effect of biaxial strain on above properties was studied. In terms of electronic structure, the results show that CrSSe, CrSTe and CrSeTe are metallic and excellent conductors of electrons. Biaxial strain does not change their metallicity, which means their electronic structure has good robustness. In terms of magnetic properties, due to the contribution of unpaired electrons in the 3d orbital of Cr atom, CrXX'(X/X' = S,Se,Te) have long range magnetic ordering. By applying tensile strain, their magnetic moments increase, and by applying compressive strain, their magnetic moments decrease. In addition, CrXX'(X/X' = S,Se,Te) have higher Curie temperature. The Curie temperature of CrSSe is 165 K, that of CrSeTe is 195 K, and that of CrSTe is 310 K, which is above the room temperature. For optical properties, the results show that CrXX'(X/X' = S,Se,Te) have excellent absorption capacity of visible and ultraviolet light, which is about 50% higher than that of typical light absorption material graphene. Their light absorption coefficients can be adjusted by applying strain, compressive strain and tensile strain can move the absorption spectrum to short wave and long wave respectively. In conclusion, this work provides theoretical guidance for the further study of the application of two-dimensional monolayer CrXX' (X/X' = S,Se,Te) in the field of new room temperature spintronic devices. [ABSTRACT FROM AUTHOR]