Abstract
New equations of motion for a Bloch electron [momentum p=h k,energy ε n(p),zone number n, charge -e]: $$m_j \frac{{dv_j }}{{dt}} = - e(E + v \times B)_j $$ are proposed, where v≡∂εn(p)/∂p is the velocity, and {mj}are the principal masses m j − 1=∂2εn/∂p j 2 along the normal and the two principal axes of curvatures at each point of the constant-energy surface represented by ε=εn(p).Their advantages over the prevalent equations of motion where the left-hand-side is replaced by hk j are demonstrated by examining de Haas-van Alphen oscillations and orientation-dependent cyclotron resonance peaks