Thermal transport in a metallic multilayer on picosecond time scales is controlled by the electronic thermal conductivity (Λe), the electronic interfacial thermal conductance (Gee), and electron-phonon coupling constant (g). We analyze heat transfer in a nanoscale Pt/Au bilayer using data obtained in pump-probe measurements and modeling using a transmission-line-equivalent circuit. For optical exciation of either the Pt or Au side of the bilayer, the majority of energy is deposited into the Pt phonons on a time scale of ≈1 ps because gPtAu and Gee>gAuhAu, where hAu is the thickness of the Au layer. We determine g of the Au layer and set a lower bound on Gee of the Pt/Au interface: gAu = 2.2 ± 0.6 × 1016 W m-3 K-1 and Gee > 5 GW m-2 K-1.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Feb 24 2014|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics