Approximation of independent electrons and single electrons play a fundamental
role in
the formation of solid electronic theory，and the movement of single
electrons in the periodic
potential field develops into energy band theory.One of the important
achievements of
energy band theory is the successful prediction of the electrical
conductivity of
crystals.However，its interpretation of the properties of transition metal
oxides has been
encountered inconsistent results.Mott first pointed out the fundamental
reason for this from a
physical point of view: the energy band theory based on the single-electron
approximation
and ignores the correlation between electrons. This article aims to
introduce the basic ideas
of the single-electron approximation and its achievements and
shortcomings，then discusses the
importance of electronic correlation in the current frontier field of
condensed matter
physics，such as superconductivity and magic angle graphene.Let students
understand that electronic
correlation effect is the link be- tween the basic knowledge of solid
physics and the frontier
science.Therefore，the explanation of electronic correla- tion effect and
its role in the field of
frontier physics should be emphasized in teaching.
Just Accepted
