Au-chains: harmonically confined intra-band plasmon on the verge of spin-polarization

Theoretical degeneracy interpretation of the single band near the Fermi level has been done along with the confinement engineering of electrons in Au-chains. Lifting of degeneracy leads to spin-asymmetry which is quantified by the spin-polarization factor. Counter effects have been investigated on intra-band plasmon. Degeneracy(non-degeneracy) and harder(softer) confinement causes a clear blue(red)-shift in plasmon energy. Results obtained are compared with experiments and it seems that plasmon in Au-chains can be understood from the competition between confinement and spin degree of freedom at maximum spin-polarization.