Atomic reconstruction and electron states at interfaces between 3C-SiC(111) and Si(110)

We report first-principles calculations that reveal atomic and electronic structures of interfaces consisting of Si(110) face and 3C-SiC (111) face in which the lattices match apparently but the atomic densities in both sides are different. We find two distinct interface structures in the total-energy difference of 4-5 meV per angstrom(2) for both the Si-Si interface and the Si-C interface: The interface of sparse Si(110) and dense SiC(111) exhibits bistability. We find that the stable and metastable structures are associated with vacant channels along a particular direction which are stabilized by the existence of over-coordinated atoms (floating bonds). We reveal that the coexistence of the floating bonds and the dangling bonds (under-coordinated atoms) and then the electron transfer from the dangling-to the floating bonds are the microscopic mechanism of the stabilization of the interface. We also find that atomic scale undulation mainly confined in the Si region also exists to stabilize the interface. The calculated interface energies show that the Si-Si interface is energetically favorable compared with the Si-C interface. Calculated energy bands exhibit semiconducting characteristics for all the stable and metastable interfaces.