关键词: T型石墨烯/
T型石墨烯衍生物-n/
电子结构/
第一原理计算
English Abstract
Structural and electronic properties of T-graphene and its derivatives
Liu Hui-Ying1,Zhang Xiu-Qin1,
Fang Yi-Mei2,
Zhu Zi-Zhong2
1.College of Science, Jimei University, Xiamen 361021, China;
2.Department of Physics, Semiconductor Optoelectronic Material and High Efficiency Conversion Device Collaborative Innovation Center, Xiamen University, Xiamen 361005, China
Fund Project:Project supported by the National key Research and Development Program, China (Grant No. 2016YFA0202601), the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 11605073), and the Scientific Research Foundation of the Education Department of Fujian Province, China (Grant No. JAT160690).Received Date:10 April 2017
Accepted Date:06 June 2017
Published Online:05 August 2017
Abstract:Recent years there has been aroused a growing interest in designing two-dimensional (2D) structures of carbon allotropes, owing to the great success in graphene. The T-graphene is a newly proposed 2D carbon allotrope possessing tetragonal symmetry other than hexagonal symmetry of graphene. Also, the energetic and dynamical stabilities of T-graphene have been revealed. So motivated, we investigate the structural stabilities and electronic properties of T-graphene and especially its derivatives-n(n=1-5) by using the first-principle calculation based on the density function theory. By changing the atomic number (n) of the linear carbon chains connecting the two tetragon rings of T-graphene, a series of sp-sp2 hybrid structures can be formed, which is named T-graphene derivatives-n. The calculation results show that the structural stabilities, chemical bond types and electronic structures of these materials depend greatly on the parity of n. Owing to a strong π-bond formed by eight carbon atoms in T-graphene, it becomes the one with the lowest energy in all these materials studied in this work. An interesting phenomenon is found that the T-graphene derivatives-n with even n are dynamically stable as witnessed by the calculated phonon spectra without imaginary modes, while those with odd n are dynamically unstable. The metallic behaviors are present in the T-graphene derivatives-n with even carbon atoms in the linear carbon chains, showing an alternating single and triple C–C bonds. Besides, we observe that the metallicity of the T-graphene derivatives-n with even n becomes stronger as n increases. On the other hand, the linear carbon chains with odd carbon atoms are comprised of continuous C=C double bonds. These T-graphene derivatives-n with odd n also show metallic behaviors, but turn into magnetic materials (except for n=1), the magnetic moments are about 0.961μB (n=3) and 0.863μB (n=5) respectively, and ferromagnetic ordering is the only possibility for the magnetism, which rarely occurs in carbon material. Our first-principle studies indicate that the introducing carbon chains between the tetragonal carbon rings of T-graphene constitute an efficient method to obtain new two-dimensional carbon allotrope. With different numbers (even or odd) of carbon atoms on the chains, the constructed 2D carbon allotropes could show contrasting dynamical and magnetic properties. These findings provide a theoretical basis for designing two-dimensional carbon materials and carbon-based nanoelectronic devices.
Keywords: T-graphene/
T-graphene derivatives-n/
electronic structure/
first-principle calculation
