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1.
J Chem Phys ; 137(15): 154707, 2012 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-23083184

RESUMO

We present a systematic comparison of the lattice structures, electronic density of states, and band gaps of actinide dioxides, AnO(2) (An=Th, Pa, U, Np, Pu, and Am) predicted by the Heyd-Scuseria-Ernzerhof screened hybrid density functional (HSE) with the self-consistent inclusion of spin-orbit coupling (SOC). The computed HSE lattice constants and band gaps of AnO(2) are in consistently good agreement with the available experimental data across the series, and differ little from earlier HSE results without SOC. ThO(2) is a simple band insulator (f(0)), while PaO(2), UO(2), and NpO(2) are predicted to be Mott insulators. The remainders (PuO(2) and AmO(2)) show considerable O2p/An5f mixing and are classified as charge-transfer insulators. We also compare our results for UO(2), NpO(2), and PuO(2) with the PBE+U, self interaction correction (SIC), and dynamic mean-field theory (DMFT) many-body approximations.

2.
Nanoscale ; 4(7): 2268-71, 2012 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-22370969

RESUMO

Highly aligned carbon nanotube (CNT) ribbons were sandwiched in epitaxial superconducting NbC films by a chemical solution deposition method. The incorporation of aligned long CNTs into NbC film enhances the normal-state conductivity and improves the superconducting properties of the assembly.


Assuntos
Condutividade Elétrica , Nanotubos de Carbono/química , Nióbio/química , Galvanoplastia/métodos , Microscopia Eletrônica de Varredura , Modelos Biológicos , Nanocompostos/química , Nanotecnologia/métodos , Propriedades de Superfície
3.
J Am Chem Soc ; 133(51): 20735-7, 2011 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-22126391

RESUMO

The synthesis of pure δ-MoN with desired superconducting properties usually requires extreme conditions, such as high temperature and high pressure, which hinders its fundamental studies and applications. Herein, by using a chemical solution method, epitaxial δ-MoN thin films have been grown on c-cut Al(2)O(3) substrates at a temperature lower than 900 °C and an ambient pressure. The films are phase pure and show a T(c) of 13.0 K with a sharp transition. In addition, the films show a high critical field and excellent current carrying capabilities, which further prove the superior quality of these chemically prepared epitaxial thin films.

4.
Chem Commun (Camb) ; 46(41): 7837-9, 2010 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-20830332

RESUMO

Epitaxial NbC thin films were grown by a chemical solution technique, polymer assisted deposition. High quality epitaxial NbC film showed a transition temperature of 10 K and a hardness of 19.54 GPa.

6.
J Am Chem Soc ; 132(8): 2516-7, 2010 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-20136140

RESUMO

Carbide films exhibit many unique properties. The development of a versatile and simple technique for the deposition of carbide films will enable a wide range of technological applications. Here we report a cost-effective chemical solution deposition or polymer-assisted deposition method for growing epitaxial carbide (including TiC, VC, and TaC) films. These epitaxial carbide films exhibit structural and physical properties similar to the films grown by vapor deposition methods.

7.
Angew Chem Int Ed Engl ; 48(8): 1490-3, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19145621

RESUMO

Film studies: Epitaxial films of BaZrN(2) (see TEM image) and BaHfN(2) are grown by polymer-assisted deposition on SrTiO(3) (STO) substrates. The films are phase-pure, allowing the intrinsic physical properties of the ternary nitrides to be studied. From 5 to 300 K, the films exhibit metallic-like resistivity-temperature behavior, with large residual resistivity ratios.

8.
Chem Commun (Camb) ; (45): 6022-4, 2008 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-19030573

RESUMO

Ultrathin epitaxial superconducting NbN (18 nm) films, exhibiting a superconducting transition temperature of 14 K and a critical current density as high as 5.2 MA cm(-2) at 5 K under zero magnetic field, were grown on SrTiO(3) (STO) by a chemical solution technique, polymer assisted deposition (PAD).

9.
J Am Chem Soc ; 130(46): 15224-5, 2008 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-18939844

RESUMO

It is indispensable to use thin films for many technological applications. This is the first report of epitaxial growth of ternary nitride AMN2 films. Epitaxial tetragonal SrTiN2 films have been successfully prepared by a chemical solution approach, polymer-assisted deposition. The structural, electrical, and optical properties of the films are also investigated.

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