Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electron cascades and secondary electron emission in graphene under
  energetic ion irradiation   Highly energetic ions traversing a two-dimensional material such as graphene
produce strong electronic excitations. Electrons excited to energy states above
the work function can give rise to secondary electron emission, reducing the
amount of energy that remains the graphene after the ion impact. Electrons can
either be emitted (kinetic energy transfer) or captured by the passing ion
(potential energy transfer). To elucidate this behavior that is absent in
three-dimensional materials, we simulate the electron dynamics in graphene
during the first femtoseconds after ion impact. We employ two conceptually
different computational methods: a Monte Carlo (MC) based one, where electrons
are treated as classical particles, and time-dependent density functional
theory (TDDFT), where electrons are described quantum-mechanically. We observe
that the linear dependence of electron emission on deposited energy, emerging
from MC simulations, becomes sublinear and closer to the TDDFT values when the
electrostatic interactions of emitted electrons with graphene are taken into
account via complementary particle-in-cell simulations. Our TDDFT simulations
show that the probability for electron capture decreases rapidly with
increasing ion velocity, whereas secondary electron emission dominates in the
high velocity regime. We estimate that these processes reduce the amount of
energy deposited in the graphene layer by 15\,\% to 65\,\%, depending on the
ion and its velocity. This finding clearly shows that electron emission must be
taken into consideration when modelling damage production in two-dimensional
materials under ion irradiation.

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The categories of this paper are: dg-ga
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th