Improvements in cathode design for high-power microwave sources are dependent on the development of novel materials that reduce the barriers to field electron emission and bypass the formation of plasmas near the cathode that degrade the devices emission characteristics. Density functional theory (DFT) can be used to calculate the electronic properties of materials surfaces and interfaces that inform multi-scale modeling of field emission events, in particular for computing band structure alignment and barrier parameters. Further, a high-throughput DFT approach could be used to identify promising materials to focus experimental efforts and accelerate the development of novel technologies.

In this project, we seek to model the structural and electronic properties of novel cathode emission materials, including coatings and carbon nanostructures, at their interfaces with metallic surfaces. This effort could include evaluation of binding of hydrocarbon precursors to various crystallographic sites on metallic surfaces; examination of the growth of nanostructures from bound hydrocarbon precursors; computation of electronic band structure in the vicinity of interfaces between nanostructures and analysis to determine system electronic properties such as contact resistance, tunneling barriers, etc.; computation of barriers to field electron emission from surfaces; and other related atomistic analyses from which system electronic properties can be derived or inferred. We additionally seek to use numerical results of DFT atomistic modeling to inform modeling of materials at the meso-scale (such as empirical potential MD or continuum models) and of HPM device physics. The ideal candidates for this effort will have a depth of experience in DFT methods and theory and experience with materials modeling at a variety of length scales as well as exposure to high performance computing environments and automated workflows for high-throughput modeling in such environments.

Keywords:

DFT, field emission, interface modeling, emission barrier, carbon nanotubes, first principles, cathodes

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral and Senior applicants