There is a one-dimensional solid lattice with two basis atoms of mass m and M, respectively (lattice constant = a). Let the interaction between atoms act only on adjacent atoms, and let the bonding force coefficient be C (Fig.). M C C a a) Draw the Brillouin zone and the approximate phonon dispersion w=w(K), and write the name of each phonon branch b) When K = TT/a, write down the normal mode energy and discuss the relative motion of adjacent atoms. c) If two atoms are of the same kind (m = M), plot the Brillouin %3D zone and phonon dispersion w=w(K).

There is a one-dimensional solid lattice with two basis atoms of mass m and M, respectively (lattice constant = a). Let the interaction between atoms act only on adjacent atoms, and let the bonding force coefficient be C (Fig.). M C C a a) Draw the Brillouin zone and the approximate phonon dispersion w=w(K), and write the name of each phonon branch b) When K = TT/a, write down the normal mode energy and discuss the relative motion of adjacent atoms. c) If two atoms are of the same kind (m = M), plot the Brillouin %3D zone and phonon dispersion w=w(K).