[en] Bronze coloured, rod-shaped crystals of Ta₅Ge₃B_y have been prepared by CO₂-LASER-techniques. X-ray-methods confirm the well known hexagonal Mn₅Si₃ type, space-group D³_6h-P6₃/mcm, a = 7.6276(6) and c = 5.2781(9) A. The Ta₆-clusters are centred by boron atoms. (orig.)

[en] In the framework of density functional theory, the first principle calculations are performed to investigate various physical properties of new series of half Heusler alloys KMnZ (Z=B, Si, Ge, As) by using WIEN2k code. The results of structural parameters show that ferromagnetic state is more stable, with Type 3, configuration than the non-magnetic and antiferromagnetic states for all KMnZ (Z=B, Si, Ge, As) compounds. All considered alloys KMnZ (Z=B, Si, Ge, As) are completely spin polarized and show half-metallic character because of the presence of band gap (BG) in minority-spin channels. The calculated magnetic moments are 3 µB, 4 µB, and 5 µB for KMnB, KMnSi (Ge), and KMnAs, respectively. The values of minority BG for KMnB, KMnSi, KMnGe, and KMnAs are 0.60 eV, 0.85 eV, 1.00 eV, and 1.20 eV, respectively. The origin of their HM gaps is also examined in addition to density of states and band structures. The Curie temperature (TC), within mean field approximation, is also calculated. The calculations for elastic constants and other mechanical parameters are computed to check the mechanical stability which revealed that all other alloys are stable with ductile nature except KMnB. From the results of several physical properties, it can be envisaged that these materials can be used for spintronic devices. (author)

[en] We investigated the delivery of small cluster ions using a source of negative ions by cesium sputtering (SNICS). The negative cluster ions of B_n, C_n, Si_n, Co_n, Cu_n, Ge_n, Au_n, GeB_n and SiB_n have been extracted by SNICS. Adequate beam current of some small clusters was obtained by changing several parameters for cluster ion yield. After a comprehensive study of the operation parameters, such as target material selection, target geometry, sputtering voltage and current, the small cluster ion current can be increased by several orders of magnitude, with little change on the monomer ion yield

[en] One of the ion implantation challenges for shallow junction formation is the production of high beam current at very low energy. Implantation of boron-containing clusters, such as B_n, SiB_n, GeB_n and B₁₀H₁₄ is a potential solution for this problem. Due to the higher cluster ion energy for the lower partial energy of the boron atom, the space-charge limit to the transport of the boron-containing cluster ion beams can be reduced by a factor of M/m, where M and m are the masses of the cluster and the boron atom, respectively. For a cluster of n boron atoms, the total gain in the cluster beam transport is nxM/m. In this paper, we will present new data on the extraction of boron-containing clusters with a Source of Negative Ions by Cesium Sputtering. For some clusters, the ion beam current can be increased by 1 to 2 orders of magnitude by adjusting the source parameters. Our experience in the successful extraction of boron-containing clusters may be useful in the design of high current ion sources

[en] The effects of the Y substitution for Gd on the structural stability and the site preference of intermetallics Gd_3_−_xY_xCo_2_9T_4B_1_0 (T=Al and Ge) are studied by using a series of interatomic pair potentials. The calculated results show Y can stabilize Gd_3_−_xY_xCo_2_9T_4B_1_0 with the tetragonal structure, and Y substitute for Gd with a strong preference for the 2b sites. The calculated lattice parameters are in good agreement with the experimental data. Furthermore, the total and partial phonon densities of states are evaluated for the Gd_3_−_xY_xCo_2_9T_4B_1_0 compounds with the tetragonal structure. A qualitative analysis is carried out with the relevant potentials for the vibrational modes, which makes it possible to predict some properties related to lattice vibration. - Graphical abstract: The lattice cell of Gd_3Co_2_9T_4B_1_0 consists of 92 atoms, or two Gd_3Co_2_9T_4B_1_0 formula units, with fourteen distinct kinds of site. Rare-earth atoms occupy 2b and 4d sites, Co atoms occupy the Co1(2c), Co2(8i1), Co3(8i2), Co4(8i3), Co5(8j1), Co6(8j2) and Co7(16k), T atoms occupy the T(8i) sites, and B atoms occupy the B1(2c1), B2(2c2), B3(8i) and B4(8j) sites. - Highlights: • The application of the pair potentials obtained from lattice-inversion method. • The lattice vibrations for Gd_3_−_xY_xCo_2_9T_4B_1_0 (T=Ge and Al) are first evaluated. • The Y atoms should prefer the 2b site of Gd_3_−_xY_xCo_2_9T_4B_1_0 compounds. • The total and partial phonon densities of states are evaluated for the Gd_3_−_xY_xCo_2_9T_4B_1_0 compounds with the tetragonal structure. • A qualitative analysis is carried out with the relevant potentials for the vibrational modes

[en] In the present paper, density functional theory (DFT) based first-principles methods are applied to investigate the mechanical and bonding properties of the newly synthesized T₂ phase superconductor Ta₅GeB₂ for the first time. The calculated lattice constants are in reasonable agreement with the experiment. The elastic constants (C_ij), bulk modulus (B), shear modulus (G), Young's modulus (Y), Poisson's ratio (v), Pugh ratio (G/B), and elastic anisotropy factor A of Ta₅GeB₂ are calculated and used to explore the mechanical behavior of the compound. To give an explanation of the bonding nature of this new ternary tetragonal system, the band structure, density of states, and Mulliken atomic population are investigated. The estimated Debye temperature and Vickers hardness are also used to justify both the mechanical and bonding properties of Ta₅GeB₂. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] Ion implantation has been a traditional and well-developed technique for junction formation in semiconductor devices for more than 30 years. However, now a big challenge to this technique is the high implant current and throughput at very low energy for ultra-shallow junction formation due to the space-charge limit on the low energy beam. Molecular ions or clusters containing B atoms, such as SiB, SiB₂, GeB, and B_n, are used as implantation ion species. Due to the mass ratio of the ion to B atom, the higher ion energy can overcome the current limit, while the B constitute carries a lower energy for shallower junction formation. Additional benefits of the bombardment by accompanied particles, such as Si and Ge on the suppression of channeling effect and TED were studied. Recoil implantation and a technique of defect engineering for junction formation were also studied. Formation of a junction of less than 30 nm was tested by both techniques