Energetics of interlayer binding in graphite: The semiempirical approach revisited
Energetics of interlayer binding in graphite: The semiempirical approach revisited
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DOI：
10.1103/physrevb.76.115424
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发表时间：
2007-09-01
影响因子：
3.7
通讯作者：
Iyetomi, Hiroshi
中科院分区：
文献类型：
--
作者：
Hasegawa, Masayuki;Nishidate, Kazume;Iyetomi, Hiroshi
在以前的工作中，我们发展了一种半经验方法来计算石墨的层间结合能[M]。Hasegawa和K. Nishidate，Phys. Rev. B 70，205431（2004）]。在本文中，我们重新审视这种方法，并开发了一种改进的方法，其中从头计算的基础上的密度泛函理论（DFT）也通过一个经验的原子-原子货车德瓦尔斯（vdW）相互作用进行校正。在DFT计算中采用了局域密度近似（LDA）和广义梯度近似（GGA）。引入参数化阻尼函数来修正渐近原子-原子vdW相互作用比以前的阻尼函数更灵活，并且在修正近似DFT计算时覆盖了更广泛的可能性。阻尼函数的经验确定施加的条件下，实验层间距，面内晶格常数，和c轴弹性常数再现。我们还需要LDA和基于GGA的方法（LDA+vdW，GGA+vdW）之间的一致性作为理论上的必要条件。在T=0 K时，用这种方法得到的层间结合能为60.4meV/atom。在室温下，通过热效应校正的类似于54 meV/atom的结果与最近的实验52 +/- 5 eV/atom一致[R. Zacharia，Phys. Rev. B 69，155406（2004）]。本半经验方法得到的原子-原子vdW相互作用有利地纠正了LDA和GGA，分别在平面能量学的石墨的过度绑定和欠绑定的性质。这种相互作用也为研究其他石墨体系如富勒烯和碳纳米管的能量学提供了一个有用的起点。
We have developed a semiempirical method to obtain interlayer binding energy of graphite in the previous work [M. Hasegawa and K. Nishidate, Phys. Rev. B 70, 205431 (2004)]. In the present paper, we revisit this approach and develop an improved method, in which ab initio calculations based on the density functional theory (DFT) are also corrected through an empirical atom-atom van der Waals (vdW) interaction. The local density approximation (LDA) and generalized gradient approximation (GGA) are used in the DFT calculations. The parametrized damping function introduced to modify the asymptotic atom-atom vdW interaction is more flexible than the previous ones and covers a wider range of possibility in correcting for the approximate DFT calculations. The damping function is determined empirically by imposing the condition that the experimental interlayer spacing, in-plane lattice constant, and c-axis elastic constant are reproduced. We also require consistency between the LDA- and GGA-based methods (LDA+vdW, GGA+vdW) as the theoretically motivated necessary condition. The interlayer binding energy obtained by this method is 60.4 meV/atom at T=0 K. The result of similar to 54 meV/atom at room temperature corrected by the thermal effect is consistent with the most recent experiment, 52 +/- 5 eV/atom [R. Zacharia , Phys. Rev. B 69, 155406 (2004)]. The atom-atom vdW interaction obtained by the present semiempirical method favorably corrects for the overbinding and underbinding nature of the LDA and GGA, respectively, in the in-plane energetics of graphite. That interaction also provides a useful starting point for the studies of energetics of other graphitic systems such as fullerenes and carbon nanotubes.