Electron-phonon coupling in graphene placed between magnetic Li and Si layers on cobalt
Electron-phonon coupling in graphene placed between magnetic Li and Si layers on cobalt
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DOI：
10.1103/physrevb.97.085132
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发表时间：
2018-02
影响因子：
3.7
通讯作者：
D. Usachov;A. Fedorov;O. Vilkov;I. Ogorodnikov;M. Kuznetsov;A. Grüneis;C. Laubschat;D. Vyalikh
中科院分区：
文献类型：
--
作者：
D. Usachov;A. Fedorov;O. Vilkov;I. Ogorodnikov;M. Kuznetsov;A. Grüneis;C. Laubschat;D. Vyalikh
利用角度分辨光电子能谱(ARPES)研究了掺锂石墨烯单层的电子结构和电子-声子耦合。基于光电子衍射测量，我们揭示了Si/Co界面的结构特性。我们的密度泛函理论计算表明，在所研究的Li/石墨烯/Si/Co体系中，Co衬底的磁性在Li和Si原子上产生了显着的磁矩。与此同时，石墨烯几乎保持非磁性，并夹在两个具有反平行磁化作用的磁性活性原子层之间。石墨烯费米表面的ARPES图显示出强电子掺杂，这可能导致电子-声子耦合(EPC)介导的超导电性。对光电子谱函数的分析揭示了EPC在k空间的明显各向异性。这些性质使得所研究的系统对于研究二维材料的超导电性与磁性之间的关系具有很大的吸引力。
Using angle-resolved photoemission spectroscopy (ARPES), we study the electronic structure and electron-phonon coupling in a Li-doped graphene monolayer decoupled from the Co(0001) substrate by intercalation of silicon. Based on the photoelectron diffraction measurements, we disclose the structural properties of the Si/Co interface. Our density functional theory calculations demonstrate that in the studied Li/graphene/Si/Co system the magnetism of Co substrate induces notable magnetic moments on Li and Si atoms. At the same time graphene remains almost nonmagnetic and clamped between two magnetically active atomic layers with antiparallel magnetizations. ARPES maps of the graphene Fermi surface reveal strong electron doping, which may lead to superconductivity mediated by electron-phonon coupling (EPC). Analysis of the spectral function of photoelectrons reveals apparent anisotropy of EPC in the k space. These properties make the studied system tempting for studying the relation between superconductivity and magnetism in two-dimensional materials.