Electronic and magnetic properties regulation of finite to infinite half sandwich organo-transition-metal-complexes functionalized graphene

• Published in: RSC advances 2016-01, Vol.6 (100), p.97953-97960
• Main Authors: Zhang, Xiuyun, Bian, Yajie, Sun, Weikang, Hu, Ting, Liu, Yongjun
• Format: Article
• Language: English
• Subjects: Electronics; Energy gaps (solid state); Graphene; Ligands; Magnetic moment; Magnetic properties; Mathematical analysis; Semiconductors
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C6RA19951H

Using first principles calculations, we systematically investigated the structural, electronic and magnetic properties of half-sandwiched organo-ligand (OL)-transition metal (TM) ligands functionalized single-layer graphene (SLG) with diverse arrangement patterns, including zero-dimension (0D) TM n OL– (OL: Bz = C 6 H 6 , Np = C 10 H 8 , Ant = C 14 H 10 , TM = Ti, Cr, Mn, Fe, n = 1, 2, 3) and 1D organometallic molecule wires, [TMC 4 H 2 ] ∞ and [TM 2 C 6 H 2 ] ∞ . In the studied structures, most TM atoms favor the hollow site of graphene, while a few favor the top site. All systems are chemically stable and the half-sandwiched TM n OL– ligands are covalently bonded with graphene. Interestingly, most TM n OL@Gs are ferromagnetic with the largest magnetic moment of 2.96 μ B for Cr 3 Ant@G 77 . In addition, ferri–ferromagnetic properties are found for Fe 2 Np@G 77 and Fe 3 Ant@G 77 , while antiferromagnetic properties are found for Ti 3 Ant@G 77 . With the exception of FeBz@G 33 , all the TMBz@G 33 and TMBz@G 66 are semiconductors and the band gap of CrBz@G 33 is as large as ∼1.0 eV. As for FeBz@G, the gap for graphene at the Dirac point is opened to 0.673 eV, 0.581 eV and 0.148 eV within the 4 × 4, 5 × 5 and 6 × 6 supercell, respectively. Moreover, the band gaps for TM 2 Np@G 77 and TM 3 Ant@G 77 are largely reduced due to the increased coverage of TM atoms. Furthermore, robust magnetic and electronic properties are found for [TMC 4 H 2 ] ∞ @G and [TMC 6 H 2 ] ∞ @G, in which the magnetic moment of [MnC 4 H 2 ] ∞ @G and [FeC 6 H 2 ] ∞ @G per cell unit is rather large at around 2.36 μ B and 4.43 μ B , respectively. Most [TMC 4 H 2 ] ∞ @Gs and [TMC 6 H 2 ] ∞ @Gs are metals, while [MnC 4 H 2 ] ∞ @G is transformed to be a semiconductor.