N and Ti adatom dynamics on stoichiometric polar TiN(111) surfaces
2016 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 649, 72-79 p.Article in journal (Refereed) PublishedText
We use molecular dynamics (MD) based on the modified embedded atom method (MEAM) to determine diffusion coefficients and migration pathways for Ti and N adatoms (Ti-ad and N-ad) on TiN(111). The reliability of the classical model-potential is verified by comparison with density functional theory (DFT) results at 0 K. MD simulations carried out at temperatures between 600 and 1800 K show that both Ti-ad and N-ad favor fcc surface sites and migrate among them by passing through metastable hcp positions. We find that N-ad species are considerably more mobile than Ti-ad on TiN(111); contrary to our previous results on TiN(001). In addition, we show that lattice vibrations at finite temperatures strongly modify the potential energy landscape and result in smaller adatom migration energies, E-a = 1.03 for Ti-ad and 0.61 eV for N-ad, compared to 0 K values E-aOK = 1.55 (Ti-ad) and 0.79 eV (N-ad). We also demonstrate that the inclusion of dipole corrections, neglected in previous DFT calculations, is necessary in order to obtain the correct formation energies for polar surfaces such as TiN(111). (C) 2016 Elsevier B.V. All rights reserved.
Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV , 2016. Vol. 649, 72-79 p.
Surface diffusion; Nitrides; Molecular dynamics; Density functional theory; Polar surfaces
IdentifiersURN: urn:nbn:se:liu:diva-130423DOI: 10.1016/j.susc.2016.01.031ISI: 000379097000012OAI: oai:DiVA.org:liu-130423DiVA: diva2:951185
Funding Agencies|Knut and Alice Wallenberg Foundation [2011.0094]; Swedish Research Council (VR) [2014-5790]; Linkoping Linnaeus Initiative LiLi-NFM [2008-6572]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials through Swedens innovation agency VINNOVA [MatLiU 2009-00971]2016-08-072016-08-052016-09-07