Evaluation of high field and/or local heating based material degradation of nanoscale metal emitter tips: a molecular dynamics analysis. (3rd April 2017)

• Record Type: Journal Article
• Authors: Zhang, Z; Giesselmann, M; Mankowski, J; Dickens, J; Neuber, A; Joshi, R P
• Is Part Of: Journal of physics. Volume 50:Number 18(2017)
• Publication Date: 2017-04-03
• Subjects: cathode degradation -- high fields -- nanoprotrusions -- molecular dynamics; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/aa6497
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: 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.