Effective Mass of Electrons in Silicon
The conduction band minimum of silicon occurs along the (100) direction, at about 85% of the way
toward the edge of the Brillouin zone along the (100) direction. This band is anisotropic. That is, the
curvature is different for the (100) direction and the directions perpendicular to it, resulting in two
different effective masses: longitudinal effective mass m_{e,l}^* = 0.98 m_0me,l∗=0.98m0 for the
(100) direction and the transverse electron mass m_{e,t}^* = 0.19 m_0me,t∗=0.19m0 for the
plane perpendicular to it. m_0 = 9.11 x 10^{-31}\: kgm0=9.11x10−31kg is the electron rest mass.
Discuss how this anisotropy would impact the density of states and conductivity of silicon.