Editing Drude model (section)

== History ==
German physicist [[Paul Drude]] proposed his model in 1900 when it was not clear whether atoms existed, and it was not clear what atoms were on a microscopic scale.<ref>{{cite web | title=Niels bohr Nobel Lecture| url=https://www.nobelprize.org/uploads/2018/06/bohr-lecture.pdf}}</ref> In his original paper, Drude made an error, estimating the Lorenz number of [[Wiedemann–Franz law]] to be twice what it classically should have been, thus making it seem in agreement with the experimental value of the specific heat. This number is about 100 times smaller than the classical prediction but this factor cancels out with the mean electronic speed that is about 100 times bigger than Drude's calculation.<ref group="Ashcroft & Mermin">{{harvnb|Ashcroft|Mermin|1976|pp=|p=23}}</ref>

The first [[Brownian motion#Einstein's theory|direct proof of atoms]] through the computation of the [[Avogadro number]] from a microscopic model is due to [[Albert Einstein]], the [[Plum pudding model|first modern model]] of atom structure dates to 1904 and the [[Rutherford model]] to 1909. Drude starts from the discovery of electrons in 1897 by [[J.J. Thomson]] and assumes as a simplistic model of solids that the bulk of the solid is composed of positively charged scattering centers, and a sea of electrons submerge those scattering centers to make the total solid neutral from a charge perspective.<ref group="Ashcroft & Mermin" name=":8">{{harvnb|Ashcroft|Mermin|1976|pp=2–3}}</ref> The model was extended in 1905 by [[Hendrik Antoon Lorentz]] (and hence is also known as the '''Drude–Lorentz model''')<ref>{{Cite journal |last=Lorentz |first=Hendrik |date=1905 |title=The motion of electrons in metallic bodies I |url=https://dwc.knaw.nl/DL/publications/PU00013989.pdf |journal=KNAW, Proceedings |volume=7 |pages=438–453 |via=KNAW}}</ref> to give the relation between the [[thermal conductivity]] and the [[electric conductivity]] of metals (see [[Lorenz number]]), and is a [[Classical physics|classical]] model. Later it was supplemented with the results of quantum theory in 1933 by [[Arnold Sommerfeld]] and [[Hans Bethe]], leading to the [[Free electron model|Drude–Sommerfeld model]].

Nowadays the Drude and [[Free electron model|Sommerfeld]] models are still significant to understanding the qualitative behaviour of solids and to get a first qualitative understanding of a specific experimental setup.<ref group="Ashcroft & Mermin" name=":7">{{harvnb|Ashcroft|Mermin|1976|pp=2}}</ref> This is a generic method in [[solid state physics]], where it is typical to incrementally increase the complexity of the models to give more and more accurate predictions. It is less common to use a full-blown [[quantum field theory]] from first principles, given the complexities due to the huge numbers of particles and interactions and the little added value of the extra mathematics involved (considering the incremental gain in numerical precision of the predictions).<ref>{{cite web  | url=https://www.youtube.com/watch?v=VF79QNugSEk&list=PLd9hKAUC3AZuo7is-aN45pmfDwJHOqKAj&index=3 | title=Solid State Physics, Lec ture 3: Drude Theory and Sommerfeld Free Electron| website=[[YouTube]]}}</ref>