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arXiv · 1706.06487

Effects of surface vibrations on interlayer mass-transport: ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands

D. G. Sangiovanni·A. B. Mei·D. Edström·L. Hultman·V. Chirita·I. Petrov·J. E. Greene
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Abstract

We carry out density-functional ab initio molecular dynamics (AIMD) simulations of Ti adatom (Tiad) migration on, and descent from, TiN <100>-faceted epitaxial islands on TiN(001) at temperatures T ranging from 1200 to 2400 K. Adatom-descent energy-barriers determined via ab initio nudged-elastic-band calculations at 0 Kelvin suggest that Ti interlayer transport on TiN(001) occurs essentially exclusively via direct hopping onto a lower layer. However, AIMD simulations reveal comparable rates for Tiad descent via direct-hopping vs. push-out/exchange with a Ti island edge atom for T >= 1500 K. We demonstrate that the effect is due to surface vibrations, which yield considerably lower activation energies at finite temperatures by significantly modifying the adatom push/out-exchange reaction pathway.

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D. G. Sangiovanni, A. B. Mei, D. Edström, L. Hultman, V. Chirita, I. Petrov, J. E. Greene. 2017-11-27. Effects of surface vibrations on interlayer mass-transport: ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands. https://doi.org/10.1103/physrevb.97.035406

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