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In the realm of multiferroicity in 2D magnets, whether magnetic and polar skyrmions can coexist within a single topological entity has emerged as an important question. Here, we study Janus 2D magnets CrInX3 (X=Se, Te) for a comprehensive investigation of the magnetic ground state, magnetic excited state, and corresponding ferroelectric polarization by first-principles electronic structure calculations and Monte Carlo simulations. Specifically, we have thoroughly elucidated the magnetic exchange mechanisms, and have fully exemplified the magnetic field dependence of the magnon spectrum. More importantly, our study reveals a previously unrecognized, remarkably large spin-spiral-induced ferroelectric polarization (up to 194.9 μC/m2) in both compounds. We propose an approach to identify polar skyrmions within magnetic skyrmions, based on the observed direct correlation between spin texture and polarization density. Elucidating this correlation not only deepens our understanding of magnetic skyrmions but also paves the way for innovative research in the realm of multiferroic skyrmions. [ABSTRACT FROM AUTHOR]

In the present work, we investigate the electronic structure and magnetism of InN nanoribbon doped with 3d Mn atoms in different positions by first-principle density functional calculations. The structural stability is described by using the calculated total energy of the doped nanoribbons including the antiferromagnetic (AFM) and the ferromagnetic (FM) coupled states. Our calculations show that the ground state is ferromagnetic regardless of the position of Mn atoms. The dependence of bandgap and spin polarization on Mn positions makes it possible to control the electronic properties by choosing the impurity position and applying these structures in nanoelectronics and spintronics. [ABSTRACT FROM AUTHOR]

Using the first-principles calculations based on density functional theory (DFT) within the generalized gradient approximation (GGA), Ti2RuAl full-Heusler compound is studied. The electronic structure, magnetic, and optical properties of Ti2-based full Heusler compound Ti2RuAl are calculated and analyzed using the Wien2k package. The CuHg2Ti-type structure is found to be more favorable than the AlCu2Mn-type structure for this compound. The Ti2RuAl Heusler compound exhibits a ferrimagnetic half-metallic behavior with the total magnetic moment of 1 µB at the equilibrium lattice constant 6.24 Å. The total magnetic moment of Ti2RuAl is in agreement with the Slater-Pauling rule mtot = ztot–18 and hence has integral magnetic moments which is due to 100% spin polarization at Fermi energy. Ti2RuAl has an energy gap in the spin-down channel of 0.229 eV. This compound keeps a 100% of spin polarization for lattice constant change in the range of 5.8–6.5 Å. The Curie temperature of Ti2RuAl is estimated to be 451 K using the mean field approximation (MFA). In addition, optical properties like dielectric function, reflectivity, energy loss function, absorption coefficient, and optical conductivity are calculated. [ABSTRACT FROM AUTHOR]

Much attention has been paid to the hidden Rashba effect exhibiting an intriguing spin-layer locking phenomenon observed in two-dimensional materials with inversion symmetry. This effect provides a new possibility for manipulating Rashba spin polarization even in centrosymmetric materials. We propose a mechanism exhibiting an unconventional hidden Rashba effect showing a unique helical spin texture in which two Fermi circles in different bands have the same spin helicity exhibiting a complete spin separation in space. We demonstrate such an unconventional hidden Rashba effect by showing the unique electronic structures of two-dimensional InTe with inversion symmetry investigated by the first-principles calculations. It is found that spins in both the inner and outer bands with the one helicity are located in the top sublayer whereas spins with the other helicity are in the bottom sublayer indicating a complete spatial spin separation. Strong spin-orbit coupling and a band inversion among two pairs of spin-degenerate bands are the main origins for the unconventional hidden Rashba involving two pairs of spin-degenerate bands rather than one pair, which gets usually involved in the conventional (hidden) Rashba effects. This new type of the hidden Rashba effect observed in two-dimensional InTe would broaden our understanding of the underlying physics of spin polarization phenomena eventually leading to a potential application in future spintronics. [ABSTRACT FROM AUTHOR]

In this work, the electronic and magnetic features of the Sc2MnSi bulk, surfaces, and the interface with the semiconductor CdTe (111) were thoroughly researched using the first-principles calculations. The Sc2MnSi alloy with equilibrium lattice constant of 6.34 Å shows half-metallic (HM) property. This alloy exhibits an energy gap and a HM gap of 0.54 and 0.12 eV, respectively. The density of states results confirm the existence of the half-metallicity property for the Sc2MnSi component at SiSc(2)-(001), Sc(2)-, and Si-(111) surfaces while this property is not revealed at Sc(1)-, Mn-terminated (111), Sc(1)Mn-terminated (001), and Sc2MnSi (110) surfaces for the same component. In addition, in the case of Sc2MnSi/CdTe interface, it is noted that Cd-Si connection does not reveal the half-metallicity feature, while the Si-Te shape exhibits a 100% spin polarization, thus preserving the half-metallicity. Furthermore, the Si-Te shape is more stable than the others, according to the interfacial adhesion energy. [ABSTRACT FROM AUTHOR]

The properties of the ground state and the electronic structure of Fe2PtZ (Z = Ga, In, Ge, Si, Sn, Al) and FeRh1 – xPtx in the framework of the density functional theory implemented in the VASP software package alloys have been studied. Densities of electronic states for Fe2PtZ and FePt are obtained. It is shown that in Fe2PtIn and FePt high values of spin polarization are observed. It has been found that with increasing platinum concentration, the staggered antiferromagnetic spin configuration becomes unstable, and in the concentration range above 0.625, the antiferromagnetic configuration with layer-by-layer alternation of magnetic moment directions becomes advantageous. It was found that with a further increase in the platinum concentration, a ferromagnetic phase is observed. [ABSTRACT FROM AUTHOR]

The structural parameters, exchange splittings, half-metallic property, electronic features and magnetic performances of Ba1−xCrxS materials were determined by utilizing the computational methods of density functional theory. The localized magnetic spins in the Ba1−xCrxS result from the effect of the hole carriers caused by the d shells of Cr atom, hybridizing with p levels of S atom. The ferromagnetism is mostly endorsed by the exchange splitting owing to its large contribution than that of the crystal field. The Ba1−xCrxS (x = 0.25), Ba1−xCrxS (x = 0.5)and Ba1−xCrxS (x = 0.75) materials have half-metallic characteristic with ferromagnetic state, where their electronic structures demonstrate spin polarizations of 100% with half-gaps of 0.815, 0.912 and 0.72 eV, respectively. Therefore, Ba1−xCrxS systems have better magneto-electronic performances, making them appropriate half-metallic materials for spin-injection applications for spintronics. [ABSTRACT FROM AUTHOR]

Based on the first-principle calculations, the electronic structure and magnetic properties of MgO materials (bulk doped with intrinsic defects, transition metal elements Co and Ni; surface doped with non-metallic elements C and N, in addition to Co and Ni) have been systematically investigated. The calculation results show that the oxygen vacancy (VO) in the MgO bulk material cannot make the system spin polarization. When magnesium vacancy (VMg) is introduced, a local magnetic moment of 1.31 μB will be produced, and the magnetic coupling between magnesium vacancies at each distance is ferromagnetic; isolated Co and Ni can produce high-spin states of S = 3/2 and 1, respectively. However, Co–Co are mainly coupled antiferromagnetically at different distances, and the magnetic coupling of Ni–Ni will produce the oscillation phenomenon between FM and AFM states. MgO (001) surface studies reveal that the spin polarization of 2p orbitals of isolated C and N may produce local magnetic states of 0.96 μB and 0.59 μB, respectively. C–C and N–N at different distances are both mainly coupled ferromagnetically. Although one single Co atom will produce a magnetic moment of 1.00 μB on the surface, Co–Co at different distances are mainly antiferromagnetic coupling, while the magnetism is not produced by Ni. Our research is beneficial to the development of spintronics. [ABSTRACT FROM AUTHOR]

We present a combined investigation of the electronic structure of bulk arc-melted full-Heusler Co 2 - x Fe 1 + x Si (x = 0, 0.5, 1) and CoFeSi alloys using density functional theory and ultrasoft X-ray emission spectroscopy. We perform first-principles calculations of the spin-polarized total and partial density of states for the Co and Fe 3d (s, p) as well as for the Si 3s (p, d) orbitals. It is demonstrated that only Co 2 FeSi alloy exhibits a half-metallic behavior. However, the inverse CoFe 2 Si alloy shows pseudogap and high spin polarization at the Fermi level. We carry out ultrasoft X-ray emission Si L 2 , 3 measurements, which provide the information about the local partial density of states of Si 3s and 3d orbitals in the valence band localized on Si atoms. We compare the measured spectra with our theoretical calculations and discuss them in terms of the contribution of s and d-electrons to the bonding. The Si and transition-metals sd and dd bonding formation is shown in the Co 2 - x Fe 1 + x Si and CoFeSi alloys. The high spin polarization values, along with the extremely high Curie temperature, make these compounds potential candidates for spintronic applications. [ABSTRACT FROM AUTHOR]

Materials with multifunctional properties are currently being studied for countless technological applications. In the present work, an experimental and theoretical study of the iron-chromite spinel FeCr2O4 produced by the solid-state reaction technique is reported. Structural analysis from x-ray diffraction experiments revealed the crystallization of the material into a cubic structure and morphological and compositional studies showed the granular character, with nanometric and micrometric dimensions whose compositions are as expected from its chemical stoichiometry. Optical characterization reveals semiconducting behavior with bandgap 1.52 eV and the magnetic response shows weak ferromagnetic character at room temperature. The density of electronic states in the ground state evidences characteristic semiconducting for one spin polarization and conducting for the other close to the Fermi level, which is compatible with a half-metallic behavior with magnetic moment of 2.0 µB per unit cell. [ABSTRACT FROM AUTHOR]

Density functional theory-based investigation of the electronic, magnetic, and optical characteristics in pure and ytterbium (Yb) doped ZnO has been carried out by the plane-wave pseudopotential technique with generalized gradient approximation. The calculated lattice parameters and band gap of pure ZnO are in good agreement with the experimental results. The energy band gap decreases with increasing Yb concentration. The Fermi level moves upward into the conduction band after doping with Yb, which shows the properties of an n-type semiconductor. New defects were created in the band-gap near the conduction band attributed to the Yb-4f states. The magnetic properties of ZnO were found to be affected by Yb doping; ferromagnetic property was observed for 4.17% Yb due to spin polarization of Yb-4f electrons. The calculated optical properties imply that Yb doped causes a blue shift of the absorption peaks, significantly enhances the absorption of the visible light, and the blue shift of the reflectivity spectrum was observed. Besides, a better transmittance of approximately 88% was observed for 4.17% Yb doped ZnO system. The refractive index and the extinction coefficient were observed to decrease as the Yb dopant concentration increased. As a result, we believe that our findings will be useful in understanding the doping impact in ZnO and will motivate further theoretical research. [ABSTRACT FROM AUTHOR]