On the Electronic Properties of Gold Quantum Dots at a Finite Temperature

Gold nanoparticles are of interest in a broad class of research fields, ranging from the basic sciences through technology to the biosciences. Not only are the environments in which they are investigated very diverse, but the temperature range is also very wide, going from cryogenic temperatures to hundreds of degrees Celsius. A primary role in all the potential applications is played by the electronic properties of the nanoparticles. While these have been studied theoretically before, less attention has been given to the potential effect of temperature on them. Here, we use a particle model and model Hamiltonian to study these possible effects by means of the finite-temperature Green function formalism. We focus in particular on how much temperature would impact observations in positron annihilation and in Compton scattering experiments. For our study, we consider temperatures ranging from −80∘C to 1000 ∘C and nanoparticle diameters ranging from 1 nm to 6 nm. We find that the temperature effects are rather small and generally at the limit of experimental resolution. Still, changes near the Fermi momentum in the Compton profiles should be observable in some cases.