Substrate-induced half-metallic property in epitaxial silicene

Department of Applied Physics, Nanjing University of Science and Technology - Nanjing 210094, China

^(a) qianyan@njust.edu.cn (corresponding author)
^(b) mrhpwu@njust.edu.cn (corresponding author)

Received: 30 March 2019
Accepted: 7 June 2019

Abstract

For most practical applications in electronic devices, two-dimensional materials should be transferred onto semiconducting or insulating substrates, since they are usually generated on metallic substrates. However, the transfer often leads to wrinkles, damages, contaminations and so on which would destroy the intrinsic properties of samples. Thus, directly generating two-dimensional materials on nonmetallic substrates has been a desirable goal for a long time. Here, via a swarm structure search method and density functional theory, we employed an insulating N-terminated cubic boron nitride(111) surface as a substrate for the generation of silicene. The result tells that the silicene exhibits a ferromagnetic half-metal with a half-metallic band gap of . This feature is driven by the strong interaction between silicon and surface nitrogen atoms. The magnetic moments are mainly located on surface nitrogen sites without bonding silicon atoms and the value is . In the spin-up channel, it behaves as a direct band gap semiconductor with a gap of , while it exhibits metallic characteristic in the spin-down channel. Besides, both the magnetic and electronic properties are not sensitive to the external compressive strain. This work maybe opens the way for the utility of silicene in the spintronic field.