Editing Condensed matter physics (section)

===Advent of quantum mechanics===
Drude's classical model was augmented by [[Wolfgang Pauli]], [[Arnold Sommerfeld]], [[Felix Bloch]] and other physicists.  Pauli realized that the free electrons in metal must obey the [[Fermi–Dirac statistics]].  Using this idea, he developed the theory of [[paramagnetism]] in 1926.  Shortly after, Sommerfeld incorporated the [[Fermi–Dirac statistics]] into the [[free electron model]] and made it better to explain the heat capacity.  Two years later, Bloch used [[quantum mechanics]] to describe the motion of an electron in a periodic lattice.<ref name=Kragh2002/>{{rp|366–368}}

The mathematics of crystal structures developed by [[Auguste Bravais]], [[Yevgraf Fyodorov]] and others was used to classify crystals by their [[symmetry group]], and tables of crystal structures were the basis for the series ''International Tables of Crystallography'', first published in 1935.<ref name=Aroyo-2006>{{Cite book|last=Aroyo|first=Mois, I.|author2=Müller, Ulrich|author3=Wondratschek, Hans|title=Historical introduction|year=2006|volume=A|pages=2–5|doi=10.1107/97809553602060000537|series=International Tables for Crystallography|isbn=978-1-4020-2355-2|url=http://www.european-arachnology.org/proceedings/19th/Lourenco.PDF|citeseerx=10.1.1.471.4170|access-date=2017-10-24|archive-date=2008-10-03|archive-url=https://web.archive.org/web/20081003122816/http://www.european-arachnology.org/proceedings/19th/Lourenco.PDF|url-status=dead}}</ref> [[Band theory|Band structure calculations]] were first used in 1930 to predict the properties of new materials, and in 1947 [[John Bardeen]], [[Walter Brattain]] and [[William Shockley]] developed the first [[semiconductor]]-based [[transistor]], heralding a revolution in electronics.<ref name=marvincohen2008 />

[[File:Replica-of-first-transistor.jpg|thumb|left|A replica of the first [[point-contact transistor]] in [[Bell labs]]]]
In 1879, [[Edwin Herbert Hall]] working at the [[Johns Hopkins University]] discovered that a voltage developed across conductors which was transverse to both an electric current in the conductor and a magnetic field applied perpendicular to the current.<ref>{{cite journal|title=On a New Action of the Magnet on Electric Currents|author=Hall, Edwin|journal=American Journal of Mathematics|volume=2|year=1879|pages=287–92|url=http://www.stenomuseet.dk/skoletj/elmag/kilde9.html|access-date=2008-02-28|doi=10.2307/2369245|issue=3|jstor=2369245|s2cid=107500183 |url-status=dead|archive-url=https://web.archive.org/web/20070208040346/http://www.stenomuseet.dk/skoletj/elmag/kilde9.html|archive-date=2007-02-08}}</ref> This phenomenon, arising due to the nature of charge carriers in the conductor, came to be termed the [[Hall effect]], but it was not properly explained at the time because the electron was not experimentally discovered until 18 years later. After the advent of quantum mechanics, [[Lev Landau]] in 1930 developed the theory of [[Landau quantization]] and laid the foundation for a theoretical explanation of the [[quantum Hall effect]] which was discovered half a century later.<ref>{{cite book|first1=L. D.|last1=Landau|first2=E. M.|last2=Lifshitz|title=Quantum Mechanics: Nonrelativistic Theory|year=1977|publisher=Pergamon Press|isbn=978-0-7506-3539-4}}</ref>{{rp|458–460}}<ref>{{cite journal|title=Focus: Landmarks—Accidental Discovery Leads to Calibration Standard|date=2015-05-15|first=David|last=Lindley|journal=Physics|volume=8|page=46 |doi=10.1103/Physics.8.46}}</ref>

Magnetism as a property of matter has been known in China since 4000 BC.<ref name=mattis-magnetism-2006>{{cite book|last=Mattis|first=Daniel|title=The Theory of Magnetism Made Simple|year=2006|publisher=World Scientific|isbn=978-981-238-671-7}}</ref>{{rp|1–2}} However, the first modern studies of magnetism only started with the development of [[electrodynamics]] by Faraday, [[James Clerk Maxwell|Maxwell]] and others in the nineteenth century, which included classifying materials as [[ferromagnetic]], [[paramagnetic]] and [[diamagnetic]] based on their response to magnetization.<ref name=Chatterjee-2004-ferromagnetism>{{cite journal|last=Chatterjee|first=Sabyasachi|title=Heisenberg and Ferromagnetism|journal=Resonance|date=August 2004|volume=9|issue=8|doi=10.1007/BF02837578|url=http://www.ias.ac.in/describe/article/reso/009/08/0057-0066|access-date=13 June 2012|pages=57–66|s2cid=123099296}}</ref> [[Pierre Curie]] studied the dependence of magnetization on temperature and discovered the [[Curie point]] phase transition in ferromagnetic materials.<ref name=mattis-magnetism-2006 /> In 1906, [[Pierre Weiss]] introduced the concept of [[magnetic domain]]s to explain the main properties of ferromagnets.<ref name=Visintin-domains>{{cite book|last=Visintin|first=Augusto|title=Differential Models of Hysteresis|year=1994|publisher=Springer|isbn=978-3-540-54793-8|url=https://books.google.com/books?id=xZrTIDmNOlgC&pg=PA9}}</ref>{{rp|9}} The first attempt at a microscopic description of magnetism was by [[Wilhelm Lenz]] and [[Ernst Ising]] through the [[Ising model]] that described magnetic materials as consisting of a periodic lattice of [[Spin (physics)|spins]] that collectively acquired magnetization.<ref name=mattis-magnetism-2006/> The Ising model was solved exactly to show that [[spontaneous magnetization]] can occur in one dimension and it is possible in higher-dimensional lattices. Further research such as by Bloch on [[spin wave]]s and [[Néel]] on [[antiferromagnetism]] led to developing new magnetic materials with applications to [[magnetic storage]] devices.<ref name=mattis-magnetism-2006/>{{rp|36–38,g48}}