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Abstract: The spin-polarized quantum transport properties of graphene nanoribbons (GNRs) adsorbed with vanadium atoms and terminated with hydrogen are investigated by density functional theory (DFT) associated with nonequilibrium Green''s function theory (NGFT). The spin current behaves nonlinearly against bias voltage for the 4-zigzag graphene nanoribbons (ZGNRs), even changing signal at certain voltages due to specific features of the coupling between molecular states and magnetic leads; For the V-adsorbed 7-armchair graphene nanoribbons (ACGNRs), the transmission coefficients is dramatical large. All these results suggest that the present structures are suitable for nanoelectronics and spintronics applications. [Copyright &y& Elsevier]

Abstract: The zero- and low-temperature behaviors of spin-1/2 two-leg ladder with staggered dimerization are investigated by the Green’s function theory. At zero temperature, the ground state phase diagram is explored, wherein the leg-dimer and rung-singlet phases are revealed, which reflect two different intrinsic gapped behaviors. The former is attributed to the bond alternation along the legs, while the latter is due to the strong rung coupling. It is found that the quantum phase transition from one to another is of the first order, which can be clearly signaled by the rung entanglement entropy. At finite temperatures, the temperature dependence of thermodynamic quantities such as the magnetic susceptibility, specific heat, thermal Drude weight and rung entanglement entropy are calculated to characterize the corresponding quantum phases. It is shown that the magnetic behaviors clearly manifest a typical antiferromagnetism at low temperature, which is in accordance with the experimental results. It is also found that the intrinsic gapped low-lying excitations are responsible for the observed thermodynamic behaviors. [Copyright &y& Elsevier]

In this paper, using first-principles calculations based on density-functional theory, the electronic structures, magnetic properties, and half-metallicity in the bulk and (001) surface of quaternary Heusler alloy CoNbMnSi are studied. For the bulk, the CoNbMnSi compound shows half-metallicity with a band gap of 0.5 eV in the down-spin direction at a equilibrium lattice constant of 5.88 Ǻ. At a similar equilibrium lattice constant, the half-metallicity confirmed in the bulk CoNbMnSi, is ruined at both NbSi- and MnCo-terminated (001) surfaces and subsurfaces. Based on the magnetic property calculations, the magnetic moments of Mn and Nb atoms at the (001) surfaces increase with respect to the corresponding bulk values, while the magnetic moment of Co and Si atoms decreases. The spin-polarization ratio clearly decreases below 75% for (001) surfaces and subsurfaces of the CoNbMnSi alloy. [ABSTRACT FROM AUTHOR]

The structural, magnetic and half-metallic properties of the bulk and (0 0 1) surface of the Co 2 TiGe full-Heusler alloy are Investigated from the first-principles projector augmented wave potential within the generalized gradient approximation. For the bulk, our calculations indicate that the Co 2 TiGe full-Heusler alloy exhibits a half-metallic ferromagnet with a total magnetic moment of 2.00 μB per formula unit at the equilibrium lattice constant of 5.87 Å. As the Co 2 TiGe (0 0 1) surfaces are found to display corrugations because of the different relaxations of the surface atoms. From the analysis of the spin-polarized density of states, we found that the half-metallicity confirmed in bulk Co 2 TiGe compound is lost at the Co–Co termination due to the surface states located at the Fermi level, but still preserved at the Ti–Ti, Ge–Ge and Ti–Ge terminations (0 0 1) surfaces with the spin polarization 100%, with smaller band gap energy due to surface states located just below the Fermi level. Comparing the atomic magnetic moments at the Co 2 TiGe (0 0 1) surfaces and bulk values, we found large differences in values at the Co–Co terminated surface. [ABSTRACT FROM AUTHOR]

Abstract: We theoretically investigate the influences of the Dzyaloshinskii–Moriya interaction (DMI) on the spin-polarized transport through a single-molecular magnets, which is weakly coupled to ferromagnetic lead- and nonmagnetic lead-R. The spin current is obtained by means of the rate-equation approach in the sequential-tunneling region. Due to the coherent superposition of the molecular state induced by the DMI, we can observe the continuous pure spin current and negative differential conductance (NDC) under the full polarization condition and polarization reversal of spin-current in the case of . These novel phenomena may be useful in the development of molecular spintronics devices. [Copyright &y& Elsevier]

Abstract: The ground-state properties and quantum entanglement of the two-leg rung-dimerized spin-1/2 Heisenberg antiferromagnetic ladders are investigated based on the Greenʼ function combined with the Bond mean-field theory. Numerical results show that the ground-state energies do not change with the rung dimerization, and the ground-state gaps are almost proportionate to the rung dimerization coefficient δ and coupling strength α. Magnetization curves and entanglement measurements demonstrate that there are five magnetic phases, which are identified in the phase diagram. Entanglement measurements in different phases exhibit distinct behaviors, implying the fundamental differences of the five magnetic phases. [Copyright &y& Elsevier]

Abstract: In this work, we have probed the structural, electronic, and magnetic properties of the (111) surface of rocksalt (RS) VPo. The first-principles full-potential linearized augmented plane-wave method is used. Bulk VPo is found to be a half-metallic ferromagnet at equilibrium lattice constant (0.59nm) with a total spin magnetic moment of 3.0μB per formula unit. At the same equilibrium lattice constant, the V-terminated (111) surface preserves the half-metallic characteristics of the bulk VPo, however, the surface states destroy the gap in the minority spin band of the Po-terminated (111) surface. We also discuss the surface stability. [Copyright &y& Elsevier]

Abstract: Compared to half-metallic ferromagnets, half-metallic antiferromagnets (precisely called half-metallic fully compensated ferrimagnets) are more promising candidates for spintronic applications since their zero magnetization leads to lower stray fields and thus tiny energy losses. Using the first-principles calculations, we have systematically investigated the electronic and magnetic properties of the ordered Cr1− x Ca x Sb alloy. It is found that Cr1− x Ca x Sb with , 0.25, 0.5 and 0.75 all are half-metals like zinc-blende CrSb and CaSb. Interestingly, Cr0.25Ca0.75Sb is a half-metallic antiferromagnet with complete spin polarization, and the half-metallic antiferromagnetism is robust against the lattice compression and expansion and the choice of electronic exchange and correlation functional. [Copyright &y& Elsevier]

• The half-metallicity verified in the bulk CsTe, it is maintained at all surfaces and subsurfaces. • The formation energy is calculated to be -2.91 eV which reveals that this compound is stable. • The spin magnetic moment of the Te-terminated (111) surface is indicated to be greatly different from the bulk values. • The calculations demonstrate the Cs-terminated (111) surface is more stable than all other surfaces. We report on the calculation of the structural, electronic, magnetic and half-metal properties of the rocksalt CsTe compound using the first principles method which is based on density functional theory. Although this compound does not possess any transitional metal in its formula, it is found to carry the half-metallic ferromagnetic property at bulk as well as the surfaces. The energy gap is equal to 3.32 eV at the equilibrium lattice constant of 7.7 Å. The formation energy is calculated to be -2.91 eV which reveals that this compound is stable. All the above-mentioned properties with the remarkable features open up the possible employment of the investigated material in several applications related to spintronics. [ABSTRACT FROM AUTHOR]

Abstract: Two-leg Heisenberg antiferromagnetic spin-1/2 ladders with asymmetric leg interactions (J 1≠J 2) are studied using the bond-mean field method. With different J 1−J 2−J ⊥ couplings, magnetization process exhibits distinct properties. For J 1:J 2:J ⊥=4:2:1 and 4:1:2, M–h curves exhibit cusp-type singularities which do not appear for J 1:J 2:J ⊥=2:1:4. Field dependence of specific heat (C v /T–h curve) has been found to be asymmetric about h m =(h 1+h 2)/2, h 1 and h 2 are two critical fields. The cusp in M–h curves and the asymmetric structure of C v /T–h curves are closely related to their energy spectrums. The linearity of specific heat in the gapless Luttinger-liquid phase and the underlying asymmetric ladder structure can be characterized by C v /T–h curves. [Copyright &y& Elsevier]

Abstract: Magnetic properties of three-leg antiferromagnetic Heisenberg spin-1/2 ladders with different dimerization patterns have been studied using the bond mean-field theory. Our results show that rung-columnar ladders are thermodynamically stable states for large rung-to-leg coupling ratios. Magnetization curves of leg-columnar and leg-staggered ladders always exhibit 0- and 2/3-magnetization plateaus, which do not appear in rung-columnar and rung-staggered ladders. In leg-dimerized ladders, the formation of spin dimers in the three legs results in the appearance of the 0- and 2/3-magnetization plateaus. Spin configuration in the 2/3-magnetization plateau can be understood from the mean-field bond parameters. [Copyright &y& Elsevier]

Abstract: The electronic and magnetic properties of the full-Heusler compound Co2MnP were studied using the full-potential augmented plane wave plus the local orbitals method within the density functional theory. Spin-polarized calculations predicted that the full-Heusler compound Co2MnP is a half-metallic ferromagnet with a magnetic moment of per formula unit and a spin-flip gap of 0.60 eV at its equilibrium lattice constant. The half-metallic ferromagnetism of the full-Heusler compound Co2MnP can be retained even when the lattice constant is changed by 1.2%. [ABSTRACT FROM AUTHOR]

• Layered blue phosphorus has a wider band gap than black phosphorus by theory. • We predict that Co/BlueP exhibits an excellent Ohmic contact compared to the other three metal (Ag, Sc, Co) structures. • In contrast, Al and Au contacted with blue phosphorus result Schottky contacts which the electronic potential barriers are larger than those for the Ohmic contacts. • The lower SBH in the Al contact can also lead to a good substrate for a Schottky contact for the 2D material. The contacted properties of metal substrates with single layer (monolayer) blue phosphorus are calculated by first principles. We analyze the charge transfer, atomic orbital overlap, electronic properties and potential barrier at the interface of metal contacted blue phosphorene (BuleP) to understand how to effectively inject electrons from the metal into the contacted blue phosphorus. We inquire into interfacial effect of blue phosphorene directly in contact with five representative metallic substrates – Au (111), Ag(111), Al(111), Co(111) and Sc(0001), which are having minimal lattice mismatch with the BlueP. We find that the contact properties of these five metals are ohmic contact and schottky contact. Of the five different contact metals, Co-BlueP heterojunction has the best electrical conductivity. The lower SBH in the Al contact can also lead to a good substrate for a Schottky contact for the heterojunction. These results can provide guidance for the future design of BlueP-based electronic devices and for the exploration of new low-dimensional semiconductor transport processes. [ABSTRACT FROM AUTHOR]

In this paper, the first-principles full-potential linearized augmented plane-wave method (FPLAPW) is implemented to investigate the structural, magnetic, and electronic properties of (001), (111) and (110) surfaces of zinc blende (ZB) structure of ScC. At the equilibrium lattice constant (5.121 Å), the half-metallicity preserved in the bulk ScC, is destroyed at both Sc(C)-terminated (001), Sc(C)-terminated (111) surfaces, as well as the ScC-terminated (110) surfaces and subsurfaces. In this study, the atomic magnetic moments were calculated, and the findings indicated that the magnetic moments are increased at the C-terminated (001), and (111) surfaces and decreased at both Sc-terminated (001) and (111) surfaces and the ScC-terminated (110) surface. The magnetic moments also increased at the Sc-terminated (001) and (111) subsurfaces, while they decreased at the C-terminated (001) and (111) subsurfaces as well as the ScC-terminated (110) subsurface. • For (111), (110) and (001)-slabs of ScC alloy, we find that the half-metallicity is ruined. • The C-terminated (111) surface has the highest spin polarization of 85.5%. • The Sc atom has lowest magnetic moments among all terminations. [ABSTRACT FROM AUTHOR]