Adeleke Adebayo A, Adeniyi Adebayo O, Tang Hu, Gou Huiyang, Yao Yansun
Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada.
Center for High Pressure Science and Technology Advanced Research, Beijing 100094, People's Republic of China.
J Phys Condens Matter. 2020 Jun 23;32(39). doi: 10.1088/1361-648X/ab96f1.
We report a new allotrope of carbon predicted from first principles simulations. This allotrope is formed in a simulated conversion of two-dimensional polymeric Cprecursor subjected to uniaxial compression at high temperature. The structure is made up of 240 carbon atoms in an orthorhombic unit cell (termed as o-C) having a mixed sp/sphybridization with the ratio of about 1:5. o-Cis stable at ambient condition and exhibits superior mechanical performance including optimum Vickers hardness (45 GPa) and fracture toughness (4.10 MPa m), outperforming most of widely used hard ceramics. The electronic structure reveals semiconducting ground state with an indirect band gap of 1.72 eV. The simple reaction pathway could accelerate discovery of this allotrope in laboratory, and the simultaneous occurrence of high fracture toughness, superhardness and semiconductivity is expected to find applications for this material.
我们报道了一种通过第一性原理模拟预测的新型碳同素异形体。这种同素异形体是在高温下单轴压缩二维聚合物C前驱体的模拟转化过程中形成的。该结构由一个正交晶胞中的240个碳原子组成（称为o-C），具有混合的sp/sp杂化，比例约为1:5。o-C在环境条件下是稳定的，并表现出优异的机械性能，包括最佳维氏硬度（45 GPa）和断裂韧性（4.10 MPa m），优于大多数广泛使用的硬质陶瓷。电子结构揭示了具有1.72 eV间接带隙的半导体基态。简单的反应途径可以加速在实验室中发现这种同素异形体，并且高断裂韧性、超硬度和半导体性的同时出现有望为这种材料找到应用。
