a) Explain that in a one-dimensional system, although a systemwith an even number of electrons per primitive unit cell isinsulator, this does not apply to three-dimensional systems.
b) How the electron state density behaves around the maximum of thevalance band and the minimum of the conductivity band of asemiconductor or insulator.
c) Explain why a fully charged band does not contribute toelectrical conductivity when an electric field is applied.
d) How does the Bloch wave vector change over time when an externalelectric field is applied in the effective mass approach?
e) Show that the state density for free electron gas is notdependent on energy in two dimensions. How to relate to energy inone and three dimensions.
