1. Suppose that an electric field is applied at 45 to the x-direction of the [100] valley in the conduction band of Si. Assume that only this valley contribute to the current. Resolve the force into components along the longitudinal and transverse directions and calculate the direction of acceleration of the electron. The transverse and longitudinal effective masses in Si are 0.2my and my respectively (my is the bare electron mass). FIGURE 2.18. (a) Brillouin zone of Si with constant-energy surfaces for the six equivalent X- valleys. (b) Enlarged view of one of the valleys, showing the longitudinal and doubly degenerate transverse masses my and mT