Plasmons in Linear Nickel-Doped Au Atomic Chains

By using the time-dependent density functional theory (TDDFT) in the time domain, we study the photoabsorption spectra of the nickel-doped Au atomic chains with up to 22 atoms, which is now possible to fabricate experimentally. It is found that the plasmon excitations can be tuned by doping Ni atoms. When the two Ni atoms substitute symmetrically the Au atoms in the chain, the dipole strength of the different transverse plasmon modes will be selectively suppressed depending on the positions of the Ni atoms, while the longitudinal plasmon mode is scarcely affected in both energy and strength. This behavior of the doping Ni atom as a local plasmonic tuner may find its applications in nanoplasmonics.