Controlling adsorbate vibrational lifetimes using superlattices

We propose using short-period superlattices as substrates to control the vibrational relaxation dynamics of adsorbate overlayers. The mass modulation of superlattices creates both band gaps and large spectral enhancements in the phonon density of states. These modifications can dramatically alter the coupling between vibrational modes of the adsorbate overlayer and the substrate lattice, thereby significantly affecting the lifetime of adsorbate modes.