Melekamburath Ajay, James Anto, Rajeevan Megha, John Chris, Swathi Rotti Srinivasamurthy
School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram, 695551, India.
Phys Chem Chem Phys. 2021 Dec 8;23(47):27031-27041. doi: 10.1039/d1cp03637h.
Recent explorations of twist in bilayer graphene and the discovery of superconducting phases at certain magic angles have laid the groundwork for a new branch in materials science called twistronics. However, theoretical studies on twisted layered materials are impeded due to the computational expense associated with first-principles calculations. Empirical force field approaches that include anisotropic terms to describe interlayer interactions have come to the fore as excellent alternatives to deal with such a stumbling block. Taking a cue from these formulations, herein, we describe our pursuit of capturing the interlayer interactions in bilayer graphynes with atomistic empirical potentials. The choice of the potentials, namely the improved Lennard-Jones potential and Hod's interlayer potential, is motivated by the objective of bringing out the role of anisotropy explicitly. Empirical parameters for both the potentials are calibrated against dispersion-corrected DFT calculations that are performed to incorporate the stacking, sliding and twisting features of the bilayer configurations. Although the isotropic improved Lennard-Jones potential is able to describe the interlayer stacking of graphynes, it is inadequate to account for the interlayer twist properties. The anisotropic Hod's interlayer potential portrays the interlayer twisting energy profiles of the benchmark DFT calculations with a reasonable accuracy. Our potential formulations can bestow impetus to the research on the homo- and hetero-bilayer structures of graphynes and other two-dimensional materials.
最近对双层石墨烯中扭曲的探索以及在某些神奇角度发现超导相，为材料科学中一个名为“扭曲电子学”的新分支奠定了基础。然而，由于与第一性原理计算相关的计算成本，对扭曲层状材料的理论研究受到阻碍。包括描述层间相互作用的各向异性项的经验力场方法已成为解决这一障碍的优秀替代方案。借鉴这些公式，在此我们描述了我们用原子经验势捕捉双层石墨炔中层间相互作用的探索。势的选择，即改进的 Lennard-Jones 势和 Hod 层间势，是出于明确突出各向异性作用的目的。这两种势的经验参数都根据色散校正的 DFT 计算进行校准，这些计算用于纳入双层构型的堆叠、滑动和扭曲特征。尽管各向同性的改进 Lennard-Jones 势能够描述石墨炔的层间堆叠，但它不足以解释层间扭曲特性。各向异性的 Hod 层间势以合理的精度描绘了基准 DFT 计算的层间扭曲能量分布。我们的势公式可为石墨炔和其他二维材料的同双层和异双层结构的研究提供动力。
