At low temperatures, the temperature dependence of heat capacity is explained by a model named for the free type of this particle.
The Klein paradox states that for a large step potential this particle's reflection coefficient is over 1. At close to absolute zero and confined to one dimension in a metal, these particles are decoupled into a holon and a spinon.  Particles of this type along with a wiggler, which is a spatially periodic magnetic field, are used to generate light in a laser named for the (*) free type of this particle. At low temperatures, the temperature dependence of heat capacity is explained by a model named for the free type of this particle. De Broglie waves for this particle were confirmed in the Davisson-Germer experiment. This particle is captured by a proton to form a neutrino and a neutron in a form of beta decay. This lepton has half integer spin. For 10 points, name this elementary particle with negative charge.
The Klein paradox states that for a large step potential this particle's reflection coefficient is over 1.
electrons