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Unexpected reconstruction of the α-boron (111) surface.

Research paper by Xiang-Feng XF Zhou, Artem R AR Oganov, Xi X Shao, Qiang Q Zhu, Hui-Tian HT Wang

Indexed on: 08 Nov '14Published on: 08 Nov '14Published in: Physical review letters



Abstract

We report a novel reconstruction of the α-boron (111) surface, discovered using ab initio evolutionary structure prediction, and show that this unexpected neat structure has a much lower energy than the recently proposed (111)-I(R,(a)) surface. In this reconstruction, all single interstitial boron atoms bridge neighboring B(12) icosahedra by polar covalent bonds, and this satisfies the electron counting rule, leading to the reconstruction-induced metal-semiconductor transition. The peculiar charge transfer between the interstitial atoms and the icosahedra plays an important role in stabilizing the surface.