This property describes why electrons form patterns in LEED. In the debate 
This property describes why electrons form patterns in LEED. In the debate resolved by this concept, Poisson argued that one side must be false since otherwise a small spot would be present, and that spot was later shown to exist by Arago. Electrons following Bragg's law after being fired at a nickel crystal provided evidence for this phenomenon in the Davisson-Germer experiment. An equation describing this phenomenon sets a certain value equal to Planck's constant over the momentum. This property is the subject of the de Broglie hypothesis. For 10 points, name this concept that resolved a debate over the nature of light by treating it as having two natures. 