Principles of the Theory of Solids

a₁ antiferromagnetic approximation argument assume atomic orbitals average b₁ Bloch Brillouin zone calculate carriers coefficients complicated components conduction band contribution corresponding crystal Debye defined density dielectric constant diffraction direction displacement effect electric field elementary energy gap example excitation factor Fermi level Fermi surface ferromagnetic formula Fourier free-electron frequency Hamiltonian holes impurity integral interaction ions k-space k₁ k₂ kinetic linear macroscopic magnetic field matrix element metal modes momentum operators optical oscillations perturbation phonon Phys plane polarization potential principle properties quantized quasi-particles reciprocal lattice vector region resonance result satisfy scattering Schrödinger equation semiconductor solid solution space specific heat sphere spin structure superconducting Suppose symmetry temperature tend tensor theorem theory thermal transition U-processes unit cell valence valence band values of q velocity Wannier functions wave-function wave-vector Wigner-Seitz cell write zero zone boundary