Emergence of magnetism in silicene by introducing carbon atom as foreign atom in all possible ways

Abstract

In spite of the unique properties of graphene and considerable efforts by various researchers in last two decades to functionalize it for tailored applications, its limitations have spurred much interest in the search of alternate two-dimensional (2D) materials beyond graphene. A new crystalline form of silicon namely ‘‘silicene’’ which is the silicon-based counterpart of grapheme has emerged out as a substitute of graphene. Motivated by novel properties of this nanomaterial, we have explored the emergence of magnetism in Silicene via introducing a C-atom as foreign atom in almost all possible ways using first principles approach. The case we have investigated are (1) pristine silicene (2) vacancy in silicene (3) C lies at adsorption site (4) C lies at adsorption site with vacancy consideration (5) C is adsorbed in the middle of two Si atoms surrounding vacancy (6) C is present as an adatom (7) C acts as substitutional dopant in silicene. Among all these, the case in which the C lies at adsorption site with vacancy consideration is found to be most stable. All cases show the ferromagnetic behavior and transition from semi conducting to metallic state; generation of magnetic moment of 2.0–2.8 µ_B on it by surface modifications. The Fermi level (E_F) is manipulated by intermixing of p-states of Si with p-states of foreign C atom are major cause of generation of magnetism inside the channel. The magnetism in silicene via C adsorption increases its potential in more compatible with current Si-based technology in comparison with graphene. These results provide better understanding for manufacturing the silicene-based nanoelectronic devices and expect to open new horizons in spintronic applications.

Keywords:

• Silicene; DFT; FPLAPW; half-metallicity; spintronics

Funding

J. Thakur would like to acknowledge DST-SERB, New Delhi for providing National Post-doctoral Fellowship vide grant no. PDF/2016/002673.