Computational Prediction of a Novel Superhard sp^(3) Trigonal Carbon Allotrope with Bandgap Larger than Diamond  

作　　者：Ruoyun Lv Xigui Yang Dongwen Yang Chunyao Niu Chunxiang Zhao Jinxu Qin Jinhao Zang Fuying Dong Lin Dong Chongxin Shan 吕若云;杨西贵;杨东问;牛春要;赵春祥;秦金旭;臧金浩;董孚颖;董林;单崇新(Henan Key Laboratory of Diamond Optoelectronic Materials and Devices,Key Laboratory of Material Physics(Ministry of Education),School of Physics and Microelectronics,Zhengzhou University,Zhengzhou 450052,China;College of Automotive Engineering,Jilin University,Changchun 130022,China)

机构地区：[1]Henan Key Laboratory of Diamond Optoelectronic Materials and Devices,Key Laboratory of Material Physics(Ministry of Education),School of Physics and Microelectronics,Zhengzhou University,Zhengzhou 450052,China [2]College of Automotive Engineering,Jilin University,Changchun 130022,China

出　　处：《Chinese Physics Letters》2021年第7期51-55,共5页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Grant Nos.11804307,U1804155,and U1604263);the China Postdoctoral Science Foundation(Grant Nos.2018M630830 and 2019T120631).

摘　　要：Searching for new carbon allotropes with superior properties has been a longstanding interest in material sciences and condensed matter physics.Here we identify a novel superhard carbon phase with an 18-atom trigonal unit cell in a full-sp^(3) bonding network,termed tri-C_(18) carbon,by first-principles calculations.Its structural stability has been verified by total energy,phonon spectra,elastic constants,and molecular dynamics simulations.Furthermore,tri-C_(18) carbon has a high bulk modulus of 400 GPa and Vickers hardness of 79.0 GPa,comparable to those of diamond.Meanwhile,the simulated x-ray diffraction pattern of tri-C_(18) carbon matches well with the previously unexplained diffraction peaks found in chimney soot,indicating the possible presence of tri-C_(18) carbon.Remarkably,electronic band structure calculations reveal that tri-C_(18) carbon has a wide indirect bandgap of 6.32 eV,larger than that of cubic diamond,indicating its great potential in electronic or optoelectronic devices working in the deep ultraviolet region.

关 键 词：electronic ULTRAVIOLET MODULUS 

分 类 号：TQ127.11[化学工程—无机化工] O469[理学—凝聚态物理]