氢掺杂单层石墨体系的晶格动力学研究

采用密度泛函理论研究了氢掺杂单层石墨（graphene）体系,并采用密度泛函微扰理论方法计算了体系局域振动模（LVMs）.结果显示,高频位置的LVMs数目与缺陷中氢原子数相等,而不同掺杂类型的LVMs频谱位置各不相同.研究结果及分析表明,LVMs测量是评估质子辐射下石墨样品的替位氢掺杂类型及其含量的有效方法,该方法可推广应用于研究其他掺杂体系. 关键词： 石墨 局域模式 晶格动力学     

Theoretical Prediction of Superconductivity in Boron Kagome Monolayer:MB3(M=Be,Ca,Sr) and the Hydrogenated CaB3

Using first-principles calculations, we predict a new type of two-dimensional(2D) boride MB₃(M = Be,Ca, Sr), constituted by boron kagome monolayer and the metal atoms adsorbed above the center of the boron hexagons. The band structures show that the three MB₃ compounds are metallic, thus the possible phononmediated superconductivity is explored. Based on the Eliashberg equation, for BeB₃, CaB₃, and SrB₃, the calculated electron–phonon coupli...     

Interaction of hydrogen molecules on Ni-doped single-walled carbon nanotube

Adsorption of hydrogen molecules on an Ni-doped (8,0) single-walled carbon nanotube (SWNT) is investigated by using first-principles density functional calculations. The result shows that a single Ni atom adsorbed on the bridge site of the tube could cannot dissociate the H₂, however it can chemisorb three H₂ at most, with the average binding energy per H₂ suitable for the hydrogen storage at the room temperature. More H₂ would physisorb around an Ni atom weakly. As for the SWNT with an Ni dimer adsorbed, we find that when the H₂ approaches the Ni--Ni bond, it dissociates without overcoming any barrier and makes bonds with Ni atom.