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In this study, the half-metallic behavior and magnetic properties of various (001) surfaces for Y 2 CrSn Heusler alloy were investigated using the spin-polarized first-principles method. The spin polarizations of the standard stable YSn-terminated and artificial stable SnSn-terminated (001) surfaces were −96.9% and −95.8%, respectively, using the generalized gradient approximation (GGA) method (−69.2% and −83.0% using the GGA + U method), and thus the two surfaces have potential use in spintronic devices. The spin polarizations of the standard YCr-terminated, artificial YY-terminated, and artificial CrCr-terminated (001) surfaces were only −43.0%, 29.3%, and −40.8%, respectively, using the GGA method (−63.2%, −67.9%, and −44.4% using the GGA + U method). The atomic magnetic moments (AMMs) of the Y and Cr atoms in the outmost layer changed greatly due to the surface states, but little change was found in the AMMs of atoms near the central layer. The average AMMs obtained for the Sn, Y, and Cr atoms using the GGA + U method were only slightly larger than the corresponding AMMs determined using the GGA method. Image 1 • Spin polarizations of stable YSn and SnSn-term (001) surfaces were high. • Spin polarizations of unstable YCr, YY, and CrCr-term (001) surfaces were low. • Atomic magnetic moments of Y and Cr atoms changed little in the outermost layer. • Little change in atomic magnetic moments of atoms near the central layer. [ABSTRACT FROM AUTHOR]

In this study, density functional theory (DFT) showed that the electronic band profiles of CaCu 3 B 2 Re 2 O 12 (B = Mn, Fe, Co, and Ni) indicate their half-metallic character. The optimized magnetic energy curves in different magnetic phases demonstrated the type-I ferrimagnetic order of all the compounds investigated in this study. The magnetic exchange coupling constants were calculated between the Cu–B, B–Re, and Cu–Re site spins using the Heisenberg model. These interactions generate strong long range Cu(↑)B(↑)Re(↓) order through a super-exchange mechanism. In these perovskites, the anti-parallel moments of Re with B and Cu reduce the net magnetic moments and they are responsible for the ferrimagnetism. The Cu and B 3d-electrons are localized and responsible for the magnetism, and the Re 5d-electrons are delocalized and responsible for the metallic nature. Magnetic susceptibility analysis verified the results estimated using DFT and the Heisenberg model. Due to the 100% spin polarization around the Fermi level, high Curie temperature TC and ferrimagnetism are expected, thereby making these materials suitable for spintronic applications. • The half-metallic character of the CaCu 3 B 2 Re 2 O 12 (B = Mn, Fe, Co and Ni) was revealed by DFT. • Heisenberg model was used for the calculating of the magnetic exchange coupling constants. • It has been shown the perspectives of the CaCu 3 B 2 Re 2 O 12 (B = Mn, Fe, Co and Ni) in spintronic applications. [ABSTRACT FROM AUTHOR]

A first-principles theoretical study of the enhanced electronic and magnetic properties of a single-layer CdS (denoted as SL-CdS) was conducted via Li substitutional doping at possible sites. Previous work shows that SL-CdS is a non-magnetic and direct bandgap semiconductor. Our work demonstrated that electronic bandgap tuned to smaller and larger values, e.g., the calculated bandgap (pseudo bandgap) for Li Cd (Li h) are 1.80 eV and 1.62 eV, respectively. Local magnetic moment induced via Li atomic doping at possible dopants sites except for Li h. The Li Cd gives a maximum magnetic moment of 0.98 μ B and shows the half-metallic character with a small dispersion for the spin-down channel at the Γ point. Among all the possible sites, the Li Cd in SL-CdS is magnetic and being most favorable thermodynamically under both S-rich and Cd-rich conditions. The Li Cd in SL-CdS indicates spin polarization with increased bandgap for spin-up and spin-down channels. In contrast, the Li S induces a magnetic moment of 0.86 μ B with a reduced bandgap of 0.60 eV for both the spin-up and spin-down channels. The partial magnetic moment is due to the fact small concentration of the dopant. Interestingly, Li h in SL-CdS shows non-magnetic semiconducting nature with decreased bandgap. For further investigation, we considered the most favorable Cd-Site. For room-temperature ferromagnetism, we did ferromagnetic and anti-ferromagnetic calculations. We considered interactions between two Li atoms substituted at far positions (1, 2) and near positions (1, 3) in SL-CdS. It was found that 2Li Cd in SL-CdS at near positions (1, 3) has FM order with Curie temperature (T c) of 339.95 K at − 5 % compressive biaxial strain. The effect of Li doping on electronic and magnetic properties of SL-CdS can help to utilize SL-CdS materials in electronics and spintronics devices applications. • We select nitrogen (Li) as a first-row element that could host spin-polarized electrons in its s-orbitals as possible sources of magnetic moment, and study various possible dopant positions. • The main aims of our study are (i) tuning of the electronic bandgap (ii) inducing magnetic moments in diamagnetic single-layer CdS. • Studying ferromagnetic (FM) and antiferromagnetic (AFM) coupling to predict the more favorable state. • Our material shows three simultaneous properties of ferromagnetism, diamagnetism and semiconducting one. • To the best of our knowledge, no 2D material is predicted to have such high temperature stability of these properties to-date. [ABSTRACT FROM AUTHOR]

The electronic structure and magnetism properties of V-doped monolayer MoS 2 under biaxial strains were researched through the first-principle calculations. The V-doped MoS 2 is a p-type semimetal with ferromagnetism (FM) state at zero strain, of which V–MoS 2 and V atom exhibit the magnetic moment of 0.81 and 0.30 μ Β , respectively. However, as the biaxial tensile strain is applied and increased gradually, the ground state changes from ferromagnetism (FM) to anti-ferromagnetism (AFM) and the magnetic moment simultaneously reduces. When the biaxial tensile strain is 3%, the ground state of the system turns into the AFM state. Moreover, under biaxial compressive strain, the system also changes from ferromagnetism (FM) to anti-ferromagnetism (AFM). The magnetism and stability of the FM state are weakened gradually due to the strengthened ionic characteristics of Mo–S bonds and the non-localization d orbitals of Mo and V atoms. The results provide a path to adjust the electronic states and magnetism characteristics of 2D transition metal dichalcogenides (TMDs), paving the way for application in spintronic devices. Slight doping with V leads to spin polarization which weakens and even disappears at large tensile strain depending on the increased ionic character of Mo and S bonds and resultant delocalization of Mo d orbitals. Image 1 • FM features of V-doped monolayer MoS 2 are weakened under tensile strain. • V-doped monolayer MoS 2 is changed into AFM state at the biaxial tensile strain of 3%. • The FM stability is lowered and even disappears because of the increased ionic character of Mo and S bonds and resultant delocalization of Mo d orbitals. [ABSTRACT FROM AUTHOR]