Abstract:  The tight bound electron model is used to calculate the energy band of hexagonal close-packed lattice. The results show that the energy band of hexagonal close packed lattice is of a special complex form, and the reason for the formation of the complex energy band is that its unique lattice structure leads to the symmetry breaking of neighboring atoms. On the plane of reciprocal space kz=0, the real part is symmetric about the kx axis and the ky axis, while the imaginary part is only symmetric about the ky axis and asymmetric about the kx axis, which is determined by the asymmetry of the next nearest neighbor atoms of the hexagonal close-packed lattice in the rectangular coordinate space. The relevant research results are not only the expansion of the teaching content of solid physics, but also provide a theoretical basis for analyzing the relevant physical properties of crystal materials.

Key words:  hexagonal close-packed lattice, tight bound electron, solid state physics