Potassium intercalation in graphite: A van der Waals density-functional study
Potassium intercalation in graphite: A van der Waals density-functional study
复制标题
DOI：
10.1103/physrevb.76.155425
复制
发表时间：
2007-04
影响因子：
3.7
通讯作者：
Eleni Ziambaras;J. Kleis;E. Schroder;P. Hyldgaard
中科院分区：
文献类型：
--
作者：
Eleni Ziambaras;J. Kleis;E. Schroder;P. Hyldgaard
用第一性原理研究了钾在石墨中的嵌入过程。钾-石墨化合物中的键合通过传统的半局域密度泛函理论（DFT）计算得到合理的解释。然而，要研究纯钾原子和石墨的插层形成能，需要使用石墨层间结合的描述，从而对非局部色散相互作用进行一致的描述。这通过货车德瓦尔斯密度泛函（vdW-DF）方法与普通DFT无缝地包括在一起[Phys. Rev. Lett. 92，246401（2004）]。发现使用vdW-DF稳定石墨晶体，晶体参数与实验相当一致。对于石墨和钾插层石墨的结构参数，如结合分离，层结合能，形成能，和体积模量的报告。此外，吸附和亚表面钾吸收能量的报告。vdw-DF描述，与传统的半局部方法相比，被发现弱软化的弹性响应。
Potassium intercalation in graphite is investigated by first-principles theory. The bonding in the potassium-graphite compound is reasonably well accounted for by traditional semilocal density functional theory (DFT) calculations. However, to investigate the intercalate formation energy from pure potassium atoms and graphite requires use of a description of the graphite interlayer binding and thus a consistent account of the nonlocal dispersive interactions. This is included seamlessly with ordinary DFT by a van der Waals density functional (vdW-DF) approach [Phys. Rev. Lett. 92, 246401 (2004)]. The use of the vdW-DF is found to stabilize the graphite crystal, with crystal parameters in fair agreement with experiments. For graphite and potassium-intercalated graphite structural parameters such as binding separation, layer binding energy, formation energy, and bulk modulus are reported. Also the adsorption and sub-surface potassium absorption energies are reported. The vdW-DF description, compared with the traditional semilocal approach, is found to weakly soften the elastic response.