By using first-principles electronic structure calculations,we predict a new two-dimensional half-metallic ferromagnet(2DHMF)with distorted square structure,i.e.,the LiCrTe_(2) monolayer.The results show that the LiCr...By using first-principles electronic structure calculations,we predict a new two-dimensional half-metallic ferromagnet(2DHMF)with distorted square structure,i.e.,the LiCrTe_(2) monolayer.The results show that the LiCrTe_(2) monolayer is dynamically,thermally,and mechanically stable,and takes a large in-plane magnetic anisotropy,a wide spin gap,a large magnetization,and a very high Curie temperature.Under a biaxial strain ranging from-5% to+5%,the ferromagnetism,half-metallicity,and high Curie temperature are maintained well.Both tensile and compressive strains can significantly increase the magnitude of the magnetocrystalline anisotropy energy(MAE)and a transition from in-plane easy-x(y)-axis to out-of-plane easy-z-axis occurs when the compressive strain exceeds 1%.Our systematic study of the LiCrTe_(2) monolayer enables its promising applications in spintronics.展开更多
By using first-principles electronic structure calculations,we propose a two-dimensional ferromagnetic semiconductor Li_(2)NiSe_(2)with a Curie temperature above 200 K.The structure of monolayer Li_(2)NiSe_(2)is dynam...By using first-principles electronic structure calculations,we propose a two-dimensional ferromagnetic semiconductor Li_(2)NiSe_(2)with a Curie temperature above 200 K.The structure of monolayer Li_(2)NiSe_(2)is dynamically stable,which is derived from the synthesized prototype compound Li_(2)Ni O_(2)and can be denoted as Li-decorated 1T-type NiSe_(2).The Ni–Se–Ni ferromagnetic superexchange dominates the magnetic couplings between the Ni atoms,which can be understood in the frame of the Goodenough–Kanamori–Anderson(GKA)rules.Our systematic study of monolayer Li_(2)NiSe_(2)enables its promising applications in spintronics and suggests a new choice to design two-dimensional ferromagnetic semiconductors.展开更多
By using first-principles electronic structure calculations, we have studied the magnetic interactions in a proposed BaZn2P2-based diluted magnetic semiconductor（DMS）. For a typical compound Ba（Zn（0.944）Mn（0.05...By using first-principles electronic structure calculations, we have studied the magnetic interactions in a proposed BaZn2P2-based diluted magnetic semiconductor（DMS）. For a typical compound Ba（Zn（0.944）Mn（0.056））2P2 with only spin doping, due to the superexchange interaction between Mn atoms and the lack of itinerant carriers, the short-range antiferromagnetic coupling dominates. Partially substituting K atoms for Ba atoms, which introduces itinerant hole carriers into the p orbitals of P atoms so as to link distant Mn moments with the spin-polarized hole carriers via the p–d hybridization between P and Mn atoms, is very crucial for the appearance of ferromagnetism in the compound. Furthermore, applying hydrostatic pressure first enhances and then decreases the ferromagnetic coupling in（Ba0.75 K0.25）（Zn（0.944）Mn（0.056））2P2 at a turning point around 15 GPa, which results from the combined effects of the pressure-induced variations of electron delocalization and p–d hybridization. Compared with the BaZn2 As2-based DMS, the substitution of P for As can modulate the magnetic coupling effectively. Both the results for BaZn2 P2-based and BaZn2As2-based DMSs demonstrate that the robust antiferromagnetic（AFM） coupling between the nearest Mn–Mn pairs bridged by anions is harmful to improving the performance of these Ⅱ–Ⅱ–Ⅴ based DMS materials.展开更多
基金the National Key R&D Program of China(Grant No.2019YFA0308603)the National Natural Science Foundation of China(Grant No.11934020)。
文摘By using first-principles electronic structure calculations,we predict a new two-dimensional half-metallic ferromagnet(2DHMF)with distorted square structure,i.e.,the LiCrTe_(2) monolayer.The results show that the LiCrTe_(2) monolayer is dynamically,thermally,and mechanically stable,and takes a large in-plane magnetic anisotropy,a wide spin gap,a large magnetization,and a very high Curie temperature.Under a biaxial strain ranging from-5% to+5%,the ferromagnetism,half-metallicity,and high Curie temperature are maintained well.Both tensile and compressive strains can significantly increase the magnitude of the magnetocrystalline anisotropy energy(MAE)and a transition from in-plane easy-x(y)-axis to out-of-plane easy-z-axis occurs when the compressive strain exceeds 1%.Our systematic study of the LiCrTe_(2) monolayer enables its promising applications in spintronics.
基金the National Key Research and Development Program of China(Grant No.2019YFA0308603)the National Natural Science Foundation of China(Grant No.11934020).
文摘By using first-principles electronic structure calculations,we propose a two-dimensional ferromagnetic semiconductor Li_(2)NiSe_(2)with a Curie temperature above 200 K.The structure of monolayer Li_(2)NiSe_(2)is dynamically stable,which is derived from the synthesized prototype compound Li_(2)Ni O_(2)and can be denoted as Li-decorated 1T-type NiSe_(2).The Ni–Se–Ni ferromagnetic superexchange dominates the magnetic couplings between the Ni atoms,which can be understood in the frame of the Goodenough–Kanamori–Anderson(GKA)rules.Our systematic study of monolayer Li_(2)NiSe_(2)enables its promising applications in spintronics and suggests a new choice to design two-dimensional ferromagnetic semiconductors.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0302903)the National Natural Science Foundation of China(Grant Nos.11774422 and 11774424)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(Grant Nos.14XNLQ03 and 16XNLQ01)
文摘By using first-principles electronic structure calculations, we have studied the magnetic interactions in a proposed BaZn2P2-based diluted magnetic semiconductor（DMS）. For a typical compound Ba（Zn（0.944）Mn（0.056））2P2 with only spin doping, due to the superexchange interaction between Mn atoms and the lack of itinerant carriers, the short-range antiferromagnetic coupling dominates. Partially substituting K atoms for Ba atoms, which introduces itinerant hole carriers into the p orbitals of P atoms so as to link distant Mn moments with the spin-polarized hole carriers via the p–d hybridization between P and Mn atoms, is very crucial for the appearance of ferromagnetism in the compound. Furthermore, applying hydrostatic pressure first enhances and then decreases the ferromagnetic coupling in（Ba0.75 K0.25）（Zn（0.944）Mn（0.056））2P2 at a turning point around 15 GPa, which results from the combined effects of the pressure-induced variations of electron delocalization and p–d hybridization. Compared with the BaZn2 As2-based DMS, the substitution of P for As can modulate the magnetic coupling effectively. Both the results for BaZn2 P2-based and BaZn2As2-based DMSs demonstrate that the robust antiferromagnetic（AFM） coupling between the nearest Mn–Mn pairs bridged by anions is harmful to improving the performance of these Ⅱ–Ⅱ–Ⅴ based DMS materials.
