What is the term for the minimum energy required to eject an electron from a material?

The minimum energy required to eject an electron from a material is known as the work function. This concept is essential in understanding the photoelectric effect, where incident light provides energy to electrons in a material, enabling them to overcome the attractive forces holding them within that material. The work function is specific to each material and represents the threshold energy that must be supplied to release an electron from the surface.

In contrast, ionization energy refers to the energy needed to remove an electron from an atom or molecule in the gas phase, which is a slightly different process than ejecting an electron from a bulk material. Binding energy generally describes the energy required to disassemble a system of particles into its constituents, and activation energy refers to the minimum energy required for a chemical reaction to occur. Each of these terms captures different aspects of energy in physics but is distinct from the work function concerning the ejection of electrons from a material.