Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultrafast heat flow in heterostructures of Au nanoclusters on
  thin-films: atomic-disorder induced by hot electrons   We study the ultrafast structural dynamics, in response to electronic
excitations, in heterostructures composed of Au$_{923}$ nanoclusters on
thin-film substrates with the use of femtosecond electron diffraction. Various
forms of atomic motion, such as thermal vibrations, thermal expansion and
lattice disordering, manifest as distinct and quantifiable reciprocal-space
observables. In photo-excited, supported nanoclusters thermal equilibration
proceeds through intrinsic heat flow, between their electrons and their
lattice, and extrinsic heat flow between the nanoclusters and their substrate.
For an in-depth understanding of this process, we have extended the
two-temperature model to the case of 0D/2D heterostructures and used it to
describe energy flow among the various subsystems, to quantify interfacial
coupling constants, and to elucidate the role of the optical and thermal
substrate properties. When lattice heating of Au nanoclusters is dominated by
intrinsic heat flow, a reversible disordering of atomic positions occurs, which
is absent when heat is injected as hot substrate-phonons. The present analysis
indicates that hot electrons can distort the lattice of nanoclusters, even if
the lattice temperature is below the equilibrium threshold for surface
pre-melting. Based on simple considerations, the effect is interpreted as
activation of surface diffusion due to modifications of the potential energy
surface at high electronic temperatures. We discuss the implications of such a
process in structural changes during surface chemical reactions.

23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio