Evaluation of high field and/or local heating based material degradation of nanoscale metal emitter tips: a molecular dynamics analysis

Z Zhang and M Giesselmann and J Mankowski and J Dickens and A Neuber and RP Joshi, JOURNAL OF PHYSICS D-APPLIED PHYSICS, 50, 185202 (2017).

DOI: 10.1088/1361-6463/aa6497

A molecular dynamics ( MD) model is used to study the potential for mass ejection from a metal nanoprotrusion, driven by high fields and temperature increases. Three- dimensional calculations of the electric fields surrounding the metal emitter are used to obtain the Maxwell stress on the metal. This surface loading is coupled into MD simulations. Our results show that mass ejection from the nanotip is possible and indicate that both larger aspect ratios and higher local temperatures will drive the instability. Hence it is predicted that in a nonuniform distribution of emitters, the longer and thinner sites will suffer the most damage, which is generally in keeping with the trends of a recent experimental report ( Parson et al 2014 IEEE Trans. Plasma Sci. 42 3982). A possible hypothesis for mass ejection in the absence of a distinct nanoprotrusion is also discussed.

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