Metal-Non-metal Transition in the Double-Donors Si:P, As and Si:P, Sb: A Simple Approach

We report the first calculation for the critical concentration Nc of the MNM transition in double-donors Si:P, As and Si:P, Sb. From an interpretation of the Hubbard model for the transition we found the result for Si:P, As in good agreement with recent experimental finding [Newman and Holcomb, Phys. Rev. Lett. 51, 2144 (1983)]. We also find that the model predicts value of Nc for Si:P, Sb in the following order NcSb < NcP,Sb < NcP < NcP,As < NcAs.