Valence Bond Order and Antiferromagnetism in Silicene - ab initio Results
Abstract
Silicene and Graphene are similar and have - bands. However band width in silicene is only a third of graphene. It results in a substantial increase in the ratio of Hubbard U to band width W, U/W 0.5 in graphene to in silicene. This enhancement, 2 dimensionality and phenomenology suggest a Mott insulator based ground state for silicene (G. Baskaran, arXiv:1309.2242). We lend support to the above proposal by showing, in an ab-initio calculation, that unlike graphene, silicene has two instabilities: i) a valence bond (Kekule) dimerization and ii) a weak two sublattice antiferromagnetic order. Presence of these instabilities, in the absence of fermi surface nesting, point to Mott localization, \textit{within the frame work of ab-initio scheme}. Substrate dependent structural reconstructions seen experimentally in silicene are interpreted as generalized Kekule bond order.
Keywords
Cite
@article{arxiv.1709.04664,
title = {Valence Bond Order and Antiferromagnetism in Silicene - ab initio Results},
author = {R. Vidya and G. Baskaran},
journal= {arXiv preprint arXiv:1709.04664},
year = {2017}
}