Monochromatic electron emitters using heavy-fermion materials

To obtain electron emission with a narrower energy width than 0.1 eV, we studied field emitters using heavy-fermion materials. These materials have f electrons with large effective mass ranging from 10 to 1000. This study used free-electron model calculations with effective mass approximation. The energy width decreased by four-fifths when effective mass increased from 1 to 200. The relationships between effective mass, f electron density, and energy width were determined. These relationships enabled us to choose materials with a narrow energy width. It was found that for an energy width narrower than 0.1 eV, f electron density must be larger than 0.05 Angstrom(-3) at an effective mass of 100 or 0.1 Angstrom(-3) nt, effective mass of 200.