外磁场下的双层类石墨烯系统的元激发能谱

Elementary Excitation Energy Spectra of Double-Layer Graphene-Like System Under External Magnetic Field

石墨烯吸附氢离子或者氟离子等或者被另一种原子替换之时可以形成类石墨烯.通过适当地调制类石墨烯可以使其具有磁性.这种类石墨烯形成的双层结构具有奇异的物理特性.为此利用不变本征算符法对外磁场下的双层类石墨烯系统的元激发能谱进行系统研究,得到体系的4支元激发谱.对元激发谱的色散规律分析得到如下结果:双层类石墨烯系统的元激发能谱出现了3个带隙ΔE21、ΔE13和ΔE34;外磁场只起到将双层类石墨烯系统的元激发能谱向高低能级平移的作用;带隙ΔE21和ΔE34出现在K对称点上,而带隙ΔE13出现在Γ对称点上;在双层类石墨烯系统因其连续对称性破缺,引起了体系带隙.

Graphene can be formed when graphene adsorbs hydrogen or fluoride ions or is replaced by another atom.Graphene-like materials can be made magnetic by proper modulation.The bilayer structure formed by this graphene-like material has strange physical properties.In this paper,the elementary excitation spectra of double-layer graphene like system under extermal magnetic field are systematically studied by using the invariant eigen operator method.The results show that there are three band gaps ΔE21,ΔE13 and ΔE34 appear in the elementary excitation energy spectra of the double-layer graphene-like system.The external magnetic field only acts as a parallel shift of the elementary excitation energy spectrum of the double-layer graphene-like system to high and low energy levels.The band gaps ΔE21 and ΔE34 appear at the point of K symmetry,while the band gapΔE 13 appears at the point ofΓsymmetry.In the double-layer graphene-like system,the band gap of the system is caused by the continuous symmetry breaking.