Temperature and Field Dependence of Energy Shifts in Energy Distribution of Field-emitted Electrons from High-Tc Superconductor Bi-2212

The utilization of superconductors as emitter material for field-emission cathodes has been investigated for the fundamental physics and practical applications of monochromatic electron emitters. The theoretical prediction of a narrow energy distribution and the empirical observation of a specific total energy distribution (TED) are the primary motivations of this study. We examined the TED of field-emitted electrons from a Bi2Sr2CaCu2Oy (Bi-2212) cathode under different temperatures and applied voltages. The observed energy distribution appeared below the Fermi level of a typical metal, and symmetrical energy distribution was observed on both the high- and low-energy sides. The peak shifted toward the low-energy side and was separated into two peaks as the applied voltage increased, a phenomenon distinctly noticeable at low temperatures. These findings are attributed to field emission that originated from the atomic site on the edge of Bi-2212, where the shift in energy level within the atoms is due to the external field.