The roughening and pinning transition on vicinal surfaces of Si(100)

Vicinal Si(100) surfaces exhibit a reconstruction with double or single steps depending on miscut and temperature. For given miscut angles the nature of the transition is investigated using a full step-step interaction. Using transfer matrix and Monte Carlo methods we find that the transition is continuous and of the pinning and roughening type defined by Chui and Weeks. Such surfaces are found to exhibit a strong mixing of double and single steps over a wide temperature range in the critical region.