Laser-initiated electron and heat transport in gold-skutterudite CoSb$_3$ bilayers resolved by pulsed x-ray scattering

TL;DR

This study investigates electron and heat transport in gold-CoSb$_3$ bilayers using pulsed x-ray scattering, revealing ballistic electron transfer and energy deposition dynamics after photo-excitation.

Contribution

It provides direct experimental evidence of ballistic electron transport and heat transfer mechanisms in bilayer nanostructures using ultrafast x-ray scattering.

Findings

Larger heat portion detected first in CoSb$_3$ layer

Evidence of ballistic electron transport from gold to CoSb$_3$

Lattice expansion correlates with energy deposition

Abstract

Electron and lattice heat transport have been investigated in bilayer thin films of gold and CoSb$_3$ after photo-excitation of the nanometric top gold layer through picosecond x-ray scattering in a pump-probe setup. The unconventional observation of a larger portion of the deposited heat being detected first in the underlying CoSb$_3$ layer supports the picture of ballistic transport of the photo-excited electrons from gold to the underlying layer. The lattice expansion recorded by x-ray scattering allows accounting for the energy deposition and heat transport.