Speakers
Description
The present work studies the growth of TaN thin films by reactive pulsed laser deposition (PLD) on MgO (001) substrates. Cross-section micrographs acquired by transmission electron microscopy (TEM) reveal that the epitaxial relation between the TaN film and the MgO substrate is $[001]_{TaN}/[001]_{MgO}$. Furthermore, the films exhibit a lattice mismatch with the substrate around 3%. In addition to the experimental measurements, first-principles DFT calculations have been performed to find a thermodynamically stable TaN/MgO interface model by evaluating it with the interface formation energy (IFE) formalism [1]. These calculations determine the most feasible model for the interface, which is a tantalum oxide layer formed between the TaN and MgO layers. Finally, the electronic properties at the interface, such as density of states (DOS) and electron localization function (ELF), were calculated. The DOS reveals a metallic behavior, with Ta-dyz and Ta-dxz degenerated orbitals mainly contributing to the states at the Fermi energy (EF). Meanwhile, the ELF shows ionic-type bonding at the interface.
This work was supported by
FORDECYT 272894, DGAPA-UNAM IG101124, IG101623, IA100624, and IN101523 projects, and CB_CONACYT A1-S-33492 grant. Calculations were performed in the DGCTIC-UNAM Supercomputing Center, Project No. LANCAD-UNAM-DGTIC-150, LANCAD-UNAM-DGTIC-368 and LANCAD-UNAM-DGTIC-422
Reference
[1] J. Guerrero-Sánchez, and Noboru Takeuchi, Formation of ferromagnetic/ferrimagnetic epitaxial interfaces: Stability and magnetic properties, Computational Materials Science, 144 (2018) 294-303. https://doi.org/10.1016/j.commatsci.2017.12.049
| Keywords | tantalum nitride, magnesium oxide, thermodynamic stability, TEM, DFT |
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| Author approval | I confirm |
| Author will attend | I confirm |