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Magnetic semiconductors, with integrated properties of ferromagnets and semiconductors, are significant for developing next‐generation spintronic devices. Herein two atomically precise clusters of dysprosium(III) tellurides, formulated respectively as [Na2(15‐crown‐5)3(py)2][(η5‐Cp*Dy)5(Te)6](py)4 (Dy5Te6, Cp*=pentamethylcyclopentadienyl; py=pyridine) and [K(2,2,2‐cryptand)]2[(η5‐Cp*Dy)6(Te3)(Te2)2(Te)3] (Dy6Te10), are reported. Crystallographic studies revealed the presence of multifarious tellurido ligands within the polyhedral cluster cores. Spectroscopic and magnetic studies showed that both clusters are single‐molecule magnets exhibiting slow magnetic relaxation behaviors at low temperatures and semiconductors with low optical band gaps comparable to benchmark semiconductors. These clusters represent probably the first lanthanide‐based molecular magnetic semiconductors. [ABSTRACT FROM AUTHOR]

Abstract Geometrically perfect S = ½ kagome lattices with frustrated magnetism are typically electrical insulators. Electron or hole doping is predicted to induce an exotic conducting state including superconductivity. Herein, an unconventional strategy of doping an S = ½ kagome lattice CoCu3(OH)6Cl2 is adopted – a structural analogue of a well‐known quantum spin liquid (QSL) candidate herbertsmithite (ZnCu3(OH)6Cl2) – by integrating it with reduced graphene oxide (rGO) via in situ redox chemistry. Such an integration drastically enhances the electrical conductivity, resulting in the transformation of an insulator to a semiconductor, corroborating the respective density of states obtained from the density functional theory calculations. Estimation of the magnetic moments, data on the Hall‐effect measurements, Bader charge analysis, and photoemission signals, altogether provide a bold signature of remote hole doping in CoCu3(OH)6Cl2 by rGO. The remote doping provides an alternative to the site doping approach to impart exotic electronic properties in spin liquid candidates, specifically, the generation of topological states like Dirac metal is envisioned.

Layer‐ and stacking‐dependent interlayer magnetism observed in bilayer CrI3${\rm CrI}_3$ has attracted a lot of attention recently. Although considerable efforts have been made, the interlayer exchange mechanism still lacks a clear physical picture. In this paper, orbital overlap‐dependent super‐super‐exchange (SSE) interactions are proposed to understand the interlayer magnetism of bilayer MX3${\rm MX}_3$ (M = Cr, Fe, and Mo; X = Cl, Br, and I) with different stacking orders. The detailed atom‐ and orbital‐resolved magnetic exchange couplings are evaluated to reveal the underlying mechanism. The results suggest that the interlayer magnetic ground state of all FeX3${\rm FeX}_3$ bilayers are antiferromagnetism (AFM) due to the t2g3eg2$t_{2g}^{3}e_{g}^{2}$ electronic configuration of Fe3+${\rm Fe}^{3+}$ cation. While CrX3${\rm CrX}_3$ and MoX3${\rm MoX}_3$ are found to possess stacking‐dependent interlayer magnetism due to the competition between AFM and ferromagnetism (FM), the dominant interlayer AFM exchange couplings are the eg−eg$e_{g}-e_{g}$ and t2g−t2g$t_{2g}-t_{2g}$ for CrX3${\rm CrX}_3$ and MoX3${\rm MoX}_3$, respectively, indicating different underlying mechanisms. These distinct interlayer magnetism can be consistently understood by the number and strength of SSE paths, which can be determined by the rule based on the orbital overlap of mediating anions. Moreover, the atom‐ and orbital‐resolved magnetic exchange couplings are also evaluated in detail, which are in good agreement with the above qualitative mechanism. This work provides detailed information and insight for understanding the stacking‐dependent interlayer magnetism, which is beneficial for the application of 2D magnetic materials. [ABSTRACT FROM AUTHOR]

We perform systematic first-principles calculations on the electronic structure of n -type magnetic semiconductor Ba(Zn $_{1-x}$ Co _x ) _2 As _2 with the facilitation of HSE06 hybrid functional. Supercells are used to consider the doping of Co atoms, and the first-principles band structures are unfolded for clarity. Based on the calculation results, magnetic states are preferred by individual Co atoms doped in Ba(Zn $_{1-x}$ Co _x ) _2 As _2 at diluted limit, and carriers are originated mainly from situations where only one Co atom exists in the nearest neighbor Zn sites out of certain doped Co atoms. The origination of carriers can be explained by the density of states and the unfolded band structure, where it is found that the scattering effects from single Co atom is small but quite large when more Co atoms are located at adjacent Zn sites. The large scattering effects of two adjacent Co atoms will alter the band structures near the Fermi-level. Carriers in Ba(Zn $_{1-x}$ Co _x ) _2 As _2 mainly originate from the As-4p orbitals, with partial contributions from the Co-3d orbitals. Our work provides new insights into the origin of the n -type carriers in magnetic semiconductors and will inspire the development of new magnetic semiconducting systems.

It has been proposed recently that 1D hybrid nanoobjects consisting of alternating double carbon chains and polycyclic carbon regions can be obtained from graphene nanoribbons of alternating width by electron irradiation. Here, based on density functional theory calculations, we show that magnetic and electronic properties of such nanoobjects can be changed dramatically by modifying the chain length and edge structure of polycyclic regions and this opens wide possibilities for spintronic applications. Nanoobjects composed of polycyclic regions with dangling bonds and even chains are found to behave as magnetic semiconductors that can generate spin-polarized currents. Band gaps of nanoobjects with odd chains change considerably upon switching between magnetic states making them promising for magnetic tunnel junctions. We also demonstrate that use of a hybrid exchange–correlation functional is important to properly describe stability of magnetic states, band gaps and synergistic effects of nanoobject components leading, for example, to magnetism in even chains. • Nanoobject properties strongly depend on chain parity and polycyclic region edges. • Nanoobjects with even chains and unsaturated edges can be magnetic semiconductors. • Nanoobjects with odd chains hold promise for magnetic tunnel junctions. • Stable magnetism in observed in odd chains and at unsaturated polycyclic region edges. • Even chains in nanoobjects can be magnetic because of non-local synergistic effects. [Display omitted] [ABSTRACT FROM AUTHOR]

Nanowires (NWs) are envisioned to be an important component of novel nanoscale electronic devices. Here, we perform atomistic simulations of coherent thermoelectric (TE) transport in free-standing ultrathin NWs of noble metals (viz. Au, Ag, Cu, Pt) cut along the [111] crystallographic direction using a non-equilibrium Greens function based first principles approach. Effect of decorating these NWs with Au or Pt atoms in an fcc environment, is also explored. Results of the calculated electronic structure show that all considered NWs, except the Pt and Pt-decorated NWs, are metallic and non-magnetic. Interestingly, Cu@Pt NW is found to be a magnetic semiconductor with an unequal band gap in ↑ − and ↓ − spin energy bands, while Pt NW and other Pt-decorated NWs (viz. Ag@Pt and Au@Pt) behave like a magnetic half-metal. To explore the TE potential of as-considered NWs, electrical conductance G , thermal conductance κ T , and thermopower S are computed in the linear response regime. Notably, the metallic NWs exhibit a quantized G. Among these, pristine NWs show a quantized value 3 G 0 up to a temperature of 200 K, while Cu@Au NW preserves its quantized value 5 G 0 even at T exceeding 300 K. In thermal transport, valence electrons make a dominant contribution to the room-temperature κ T of pristine NWs. The phononic contribution κ p h , however, goes up following decoration, with Pt-decorated NWs showing a pronounced increment (by a factor of ∼ 2). But, these NWs undergo a simultaneous reduction in the electronic contribution κ e l owing to half-metallic conduction, resulting in a net suppression of total thermal conductance κ T. Moreover, Pt-decorated NWs show a manifold enhancement in zero-bias S , with Ag@Pt exhibiting the highest value ∼ 119 μ V/K. However, S can be augmented considerably by adjusting the chemical potential μ of electrodes, and an overall best S ∼ − 890 μ V/K is found in Au NW for μ = 0. 575 eV. In this way, TE figure of merit Z T is tunable in pristine NWs over the range 1 − 3. 7. Correspondingly, the decorated NWs exhibit somewhat smaller S and Z T. Furthermore, spin-asymmetric electronic transport in Pt and Pt-decorated NWs results in net spin conductance G s and spin thermopower S s. It is found that the spin figure of merit Z s T , as high as 3.5, can be attained in Pt NW by controlling μ. Thus, noble metals NWs can be tailored for both thermoelectric and spin-thermoelectric applications. We have also investigated TE transport for the pristine NWs in the [110] direction, and found S and Z T to be comparatively much smaller. Such NWs may be useful as interconnects for low noise applications. • Thermoelectric transport in free-standing NWs of noble metals cut along the [111] direction. • Decoration of Cu NW with Pt makes it a magnetic semiconductor. • An overall best S ∼ − 890 μ V/K in Au NW for μ = 0. 575 eV. • ZT in pristine NWs over the range 1 – 3.7. • A decent Z c T ∼ 0. 48 and Z s T ∼ 0. 33 in Ag@Pt NW for μ = 0. [ABSTRACT FROM AUTHOR]

Oxygen in solids usually exists in an O 2- ionic state. As a result, it loses its magnetic nature of a single atom, wherein two unpaired electrons exist in its outer 2p orbitals. Here, it is shown that an unconventional stable ionic state of O - is realized in a new semiconductor material Sr 2 AlO 4 , leading to an intrinsic p-orbital ferromagnetism stable until ≈900 K. Experimental and theoretical investigations have clarified that one-fourth of the oxygen atoms in Sr 2 AlO 4 are insufficiently bonded in the crystal structure, resulting in a unique O - -state and p-orbital ferromagnetism. To date, the O - state is reported to exist only in non-equilibrium conditions, and p-orbital magnetism is only suggested in impurity bands with small ferromagnetic moments. The present work provides a new route for creating ferromagnetism in semiconductors and exploring new p-orbital physics and chemistry. In addition, the material shows elastic-mechanoluminescence that may enable unprecedented mechano-photonic-spintronics., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Over the past five years, significant progress has been made in understanding the magnetism and electronic properties of CaAl 2 Si 2 -type Eu M 2 X 2 ( M = Zn, Cd; X = P, As) compounds. Prior theoretical work and experimental studies suggested that EuCd 2 As 2 had the potential to host rich topological phases, particularly an ideal magnetic Weyl semimetal state when the spins are polarized along the c axis. However, this perspective is challenged by recent experiments utilizing samples featuring ultra-low carrier densities, as well as meticulous calculations employing various approaches. Nonetheless, the Eu M 2 X 2 family still exhibit numerous novel properties that remain to be satisfactorily explained, such as the giant nonlinear anomalous Hall effect and the colossal magnetoresistance effect. Moreover, Eu M 2 X 2 compounds can be transformed from semiconducting antiferromagnets to metallic ferromagnets by introducing a small number of carriers or applying external pressure, and a further increase in the ferromagnetic transition temperature can be achieved by reducing the unit cell volume. These features make the Eu M 2 X 2 family a fertile platform for studying the interplay between magnetism and charge transport, and an excellent candidate for applications in spintronics. This paper presents a comprehensive review of the magnetic and transport behaviors of Eu M 2 X 2 compounds with varying carrier densities, as well as the current insights into these characteristics. An outlook for future research opportunities is also provided., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

TiO 2 solid solutions with Fe compositions of 6 %, 9 %, and 12 % were analyzed using multi-phase Rietveld refinement analysis for average structure and maximum entropy for electronic structure. VSM analysis showed that the 9 % and 12 % Fe doped TiO 2 compositions had a maximum magnetization of 0.3128 emu/g and coercivity of 574 Oe and 568 Oe, respectively. This confirms ferromagnetic tuning with Fe doping at or above 9 %. The MEM electron density at the bond critical points (BCP) of the apical and equatorial (Ti/Fe)–O bonds in 12 % Fe-doped TiO 2 is 1.088 e/Å3 and 0.8652 e/Å3, indicating polar covalent bond. This work primarily examines a new empirical correlation between MEM electron density and magnetic parameters. Fe: TiO 2 solid solutions have high magnetization and coercivity due to strong and identical (Ti/Fe) – O apical and equatorial polar covalent bonding, with low interstitial charge buildup at non-regular tetrahedral rutile lattice sites. [ABSTRACT FROM AUTHOR]

• Electronic and magnetic properties of Fe-doped chalcopyrite-type ZnSnAs 2 semiconductors by DFT calculations. • Magnetic exchange interaction between two Fe atoms substituting Zn and Sn sites in the supercell with different geometries. • The occupation of Sn sites by Fe atoms prefers the ferromagnetic state. • Magnetic chalcopyrites have potential as promising materials in spintronic applications. The electronic and magnetic properties of Fe-doped ZnSnAs 2 within chalcopyrite structures have been studied by first-principles calculations using the density functional theory (DFT) full-potential linearized augmented-plane-wave method and the plane-wave pseudopotential methods. The band gap of ZnSnAs 2 was determined to be 0.816 eV using the modified Beck-Jonson (mBJ) exchange potential. When Fe dopants substitutionally replace Sn atoms, half-metallic ferromagnetism is observed in ZnSnAs 2 where in the spin-down band at the Fermi level is entirely unoccupied. The magnetic exchange interaction between two Fe atoms substituting Zn and Sn sites in the supercell with different geometries has been studied. The total energy difference (ΔE) between the antiferromagnetic (AFM) and ferromagnetic (FM) configurations suggests that Fe atom occupation of Zn sites in ZnSnAs 2 leads to a predominantly AFM state, while the Fe atom occupation of Sn sites prefers the FM state. [ABSTRACT FROM AUTHOR]

Magnetic semiconductors have the potential to push the boundaries of emerging technologies like spintronics. They could change the way we process and store data by leveraging not just the electron charges, but also their intrinsic spin. Materials with low dimensionality, specifically one- or two-dimensional materials, are key to this advancement. Within this category, one-dimensional semiconductors with either antiferromagnetic or ferromagnetic properties are particularly interesting for their electronic and magnetic properties. However, creating and maintaining stable ferromagnetic ordering in these semiconductors is not straightforward. There are significant challenges, such as issues due to the disorder of dopants in dilute magnetic semiconductors, or stability problems in two-dimensional magnetic materials like chromium triiodide (CrI 3). In this work, we show a potential solution in VS 4 nanowires, a one-dimensional material found in patronite minerals. These nanowires can have four magnetic orderings: two antiferromagnetic (AFM1 and AFM2), one ferrimagnetic (FI), and one ferromagnetic (FM) ordering, which we can access using different strains. We observe two magnetic phase transitions with strains in the plastic (non-linear) regime. The nanowire transitions from AFM1 to AFM2 with ɛ z = 6. 8 %, and from AFM2 to FM with ɛ z = 11. 8 %. This ability to tune the magnetic phases in a semiconductor material opens up a vast range of opportunities for their integration into spintronic devices. We believe that the range of magnetic phases in a one-dimensional semiconductor, like VS 4 nanowires, could lead to the enhanced control of both charge and spin in nanotechnology devices. • One-dimensional exfoliable material from bulk, including from the mineral Patronite. • An antiferromagnetic semiconductor with an indirect band gap of 1.22 eV. • Magnetic phase transitions with the application of strain. • Ferromagnetic semiconductor for high strains in the plastic regime. [ABSTRACT FROM AUTHOR]