Nulakani Naga Venkateswara Rao, Ali Mohamad Akbar, Subramanian Venkatesan
Centre for High Computing, CSIR-Central Leather Research Institute (CSIR-CLRI), Sardar Patel Road, Adyar, Chennai, 600020, India.
Department of Chemistry, College of Art and Science, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, UAE.
Chemphyschem. 2023 Nov 2;24(21):e202300266. doi: 10.1002/cphc.202300266. Epub 2023 Sep 18.
In the present study, a novel and unconventional two-dimensional (2D) material with Dirac electronic features has been designed using sulflower with the help of density functional theory methods and first principles calculations. This 2D material comprises of hetero atoms (C, S) and belongs to the tetragonal lattice with P /nmm space group. Scrutiny of the results show that the 2D nanosheet exhibits a nanoporous wave-like geometrical structure. Quantum molecular dynamics simulations and phonon mode analysis emphasize the dynamical and thermal stability. The novel 2D nanosheet is an auxetic material with an anisotropy in the in-plane mechanical properties. Both composition and geometrical features are completely different from the conditions necessary for the formation of Dirac cones in graphene. However, the presence of semi-metallic nature, linear band dispersion relation, massive fermions and massless Dirac fermions are observed in the novel 2D nanosheet. The massless Dirac fermions exhibit highly isotropic Fermi velocities (v =0.68×10 m/s) along all crystallographic directions. The zero-band gap semi metallic features of the novel 2D nanosheet are perturbative to the electric field and external strain.
在本研究中，借助密度泛函理论方法和第一性原理计算，利用硫花设计了一种具有狄拉克电子特性的新型非常规二维（2D）材料。这种二维材料由杂原子（C、S）组成，属于具有P/nmm空间群的四方晶格。对结果的仔细研究表明，二维纳米片呈现出纳米多孔波状几何结构。量子分子动力学模拟和声子模式分析强调了其动力学和热稳定性。这种新型二维纳米片是一种平面内力学性能具有各向异性的负泊松比材料。其组成和几何特征与石墨烯中形成狄拉克锥所需的条件完全不同。然而，在这种新型二维纳米片中观察到了半金属性质、线性带色散关系、大质量费米子和无质量狄拉克费米子的存在。无质量狄拉克费米子在所有晶体学方向上都表现出高度各向同性的费米速度（v = 0.68×10 m/s）。这种新型二维纳米片的零带隙半金属特性对电场和外部应变具有微扰性。
