First Principles Study of Optical Losses in Transition Metals and Alloys

Detailed understanding of the physics of optical losses in transition metals is a hot area of modern fundamental science with variety of applications in nano-physics, nano-photonics and nano-plasmonics. The first principles density functional theory is applied to study effects of molecular adsorption on silver (111) oriented nano-films and the alloying effects of Ag$_{1-x}$Cd$_{x}$, and Ag$_{1-x}$In$_{x }$based nanostructures on their optical losses. Optical functions are calculated within the Random Phase Approximation approach. Optical absorption spectra corresponding to the plasmon and band-to-band transitions of alloys show opposite trends in spectral shifts caused by a variation of the content, $x$. With increase of $x$, the electronic energies of band-to-band transitions associated with optical excitations of $d-$electrons indicate well pronounced red shifts. The predicted variations of optical absorption spectra of transition metals alloys agree with experimental data measured on Ag-In and Ag-Cd alloys.