arXiv subjects

M. G. Moreno-Armenta

Publications and source records attributed to M. G. Moreno-Armenta.

3 recordsLinked to original sources

arXiv2008

The Laser Ablation Production of Platinum Nitride and its Possible Structure

The synthesis of platinum nitride by the laser ablation method is reported. The spectroscopic results show that nitrogen is in interstitial sites of platinum as N-units, contradicting the accepted configuration for PtN2 where it is as N2-units. To elucidate this point we did density functional calculations to correlate composition with nitrogen sites. For dilute nitrogen concentrations, x < 0.2, nitrogen would be in six-fold coordinated sites (octahedral interstices) as N-units. For 0.2 < x < 1.5, nitrogen would be in tetrahedral interstices as N-units. Only for x > 1.5 the N2-configuration in octahedral sites is attained.

cond-mat.mtrl-sci↗

arXiv2008

Theoretical study on the possibility of bipolar doping of ScN

Scandium nitride (ScN) is a semiconducting transition metal nitride for which there are not identified dopants. We present local density functional calculations, in supercell approach, for ScN doped with O and C in N-sites and Ca and Ti in Sc-sites. Small additions of these atoms have the effect of shifting the Fermi level within the electronic band structure. O and Ti bring occupied states in bottom of conduction band, while C and Ca produces holes in top of valence band. Based on the theory we propose that bipolar doping is possible to scandium nitride.

cond-mat.mtrl-sci↗

arXiv2007

First Principles Study on the Formation of Yttrium Nitride in Cubic and Hexagonal Phases

We have studied the formation of yttrium nitride in which the Y-atoms were arranged in two common close-packed stacking: The AB-stacking (hcp-symmetry) is the ground state of metallic yttrium; while the ABC-stacking (fcc-symmetry) is the ground state of yttrium nitride. Given the different symmetries between YN and Y, there must be a phase transition (hcp->fcc) as N is incorporated in the Y-lattice. By means of first principles calculations we have made a systematical investigation where N was gradually incorporated in octahedral interstices in AB and ABC stacking of Y. We report the heat of formation, bulk modulus, lattice parameter and electronic structure of the resultant nitrides. We found that both metal arrangements are physically achievable. Furthermore, for low nitrogen incorporation the two phases may coexist. However for high nitrogen concentration the cubic phases are favored by a 30 kJ mol-1 margin. These results are important since fcc-YN is semiconducting and could be utilized as active layer in electronic devices.

cond-mat.mtrl-sci↗