Theories of low-macroscopic-field electron emission

Summary form only given. Low-macroscopic-field (LMF) electron emission is the experimental phenomenon whereby field-induced electron emission occurs from a thin dielectric film at applied field values much lower than the barrier fields (around 2 V/nm) at which cold field electron emission occurs. The films involved are often nanocomposite and electrically heterogeneous. An essential part of the problem is to capture the complexity of the physical situation. There are a multiplicity of possible emission mechanisms, and a multiplicity of detailed theories. This paper outlines a high-level conceptual framework/classification that attempts to include within it the main features of the detailed theories of LMF emission put forward in recent years. An aim is to capture, in a structured way, most of the main possible paradigms for LMF emission. The framework generalises and extends a previous attempt to do this.