RELATIVISTIC THEORY OF TAMM SURFACE STATES

A relativistic study is made of the surface states of one-dimensional heavy atomic crystals. Adopting Tamm's procedure, the Dirac equation is solved for a perturbed Kronig-Penney potential. Depending on certain existence conditions, the surface states can be classified into two categories, called relativistic Tamm and Dirac surfaces states. In the non-relativistic limit, the Dirac states disappear and the relativistic Tamm states become the well-known Tamm surface states. A detailed discussion is given of the surface energy spectrum.