2 X 4 MISSING DIMER RECONSTRUCTION MODELS OF CUBIC BORON NITRIDE (001)

摘要

Missing dimer models which conform to the electron-hole counting rule have been found energetically favourable for other 3-5 semiconductor materials. We perform molecular cluster calculations using the AM1 :Hamiltonian to study several of these models for the nitrogen-terminated c-BN(001) surface, and compare them with structures terminated with a full coverage of nitrogen dimers or N-N bridges. We find that the energetics is dominated by elastic distortion effects related to the different atomic sizes of boron and nitrogen atoms, and the counting rule is not a reliable guideline for c-BN. The most favourable models are those with a low nitrogen coverage and N-N bridges rather than dimers. References: 38