Segregation of S at Mo(001)/MoSi2(001) interface

The interface stability and electronic properties of Mo(001)/MoSi2(001) interface have been studied by the first-principles calculations based on density functional theory. According to the work of separation and charge density, these influences of sulfur on the interface adhesion of Mo/MoSi2 were revealed, and the preventing effect of Hf on the interface segregation of S was investigated. The results show that the interface structure of Mo(001)/MoSi2(001) prefers to the hollow coordination, and the separation planes of three different terminated structures with hollow coordinations are all Si–Si layers on the MoSi2 block of the interface. The calculations also suggest that S can segregate at Mo(001)/MoSi2(001) interface, and the interface segregation of S would further cause the electrons deficiency of adjacent Si–Si layer on the MoSi2 block, which is unfavorable to the interface adhesion. Alloying Mo with Hf can pin effectively S in bulk Mo system to prevent the interface segregation of S. Our calculated work should help to the composition design and interfacial control of the new refractory metal/silicide coating system.