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.