Recent content by benz994

Thank you for the responce. I think ##a## is a given quantity. ##a## is the size of the unit cell in one-dimensional lattice. The above equation is satisfied only when ##a=1##.

Homework Statement In Kittel's 'Introduction to solid state physics' (8th ed.), on page 167, it says "The wave functions at the Brillouin zone boundary ##k=\pi/a## are ##\sqrt{2} cos (\pi x/a)## and ##\sqrt{2} sin(\pi x/a)##, normalized over unit length of line." Here I cannot understand...