Question

Which of the following statements are true about effective mass?
A. Effective mass arises due to interaction of electrons with periodic potential of lattice
B. The curvature of the band determines the electron effective mass
C. Effective mass cannot be negative
D. The calculation of effective mass takes into account the shape of energy bands in 3-D k-space
E. Effective mass of an electron is given by $m^* = \frac{\hbar}{\left(\frac{d^2E}{dk^2}\right)}$
Choose the correct answer from the options given below :

• A. A, B, E only
• B. A, B, D only
• C. B, C, D only
• D. A, B, C, D only

Hint:

Always double-check formulas for correct exponents! A missing square on $\hbar$ makes the equation dimensionally invalid. Also, remember that a negative effective mass for an electron is exactly what gives rise to the concept of a "hole" in semiconductors.

Answer 1

The Correct Option is B