title: Gigahertz Dielectric Polarization of Substitutional Single Niobium Atoms in Defective Graphitic Layers.
abstract: We synthesize two Nb/C composites with an order of magnitude difference in the density of single niobium atoms substituted into defective graphitic layers. The concentration and sites of single Nb atoms are identified using aberration-corrected scanning transmission electron microscopy and density functional theory. Comparing the experimental complex permittivity spectra reveals that a representative dielectric resonance at ∼16  GHz originates from the intrinsic polarization of single Nb atom sites, which is confirmed by theoretical simulations. The single-atom dielectric resonance represents the physical limit of the electromagnetic response of condensed matter, and thus might open up a new avenue for designing electromagnetic wave absorption materials. Single-atom resonance also has important implications in understanding the correlation between the macroscopic dielectric behaviors and the atomic-scale structural origin.
authors.affiliation: Key Laboratory for Anisotropy and Texture of Materials (MOE), School of Materials Science and Engineering, Northeastern University, Shenyang 110819, P. R. China.|National Research Council Canada, 75, de Mortagne, Boucherville, Québec J4B 6Y4, Canada.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.|Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, P. R. China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Guo
authors.affiliation: Beijing Computational Science Research Center, Beijing 100084, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Guan
authors.affiliation: Key Laboratory for Anisotropy and Texture of Materials (MOE), School of Materials Science and Engineering, Northeastern University, Shenyang 110819, P. R. China.
authors.forename: Gaowu
authors.initials: G
authors.lastname: Qin
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.|Department of Materials Science and Engineering, National University of Singapore, Singapore 117576, Singapore.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Pennycook