Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhancement of electron transport and bandgap opening in graphene
  induced by adsorbates   Impurities are unavoidable during the preparation of graphene samples and
play an important role in graphene's electronic properties when they are
adsorbed on graphene surface. In this work, we study the electronic structures
and transport properties of a two-terminal zigzag graphene nanoribbon (ZGNR)
device whose scattering region is covered by various adsorbates within the
framework of the tight-binding approximation, by taking into account the
coupling strength $\gamma$ between adsorbates and carbon atoms, the adsorbate
concentration $n_i$, and the on-site energy disorder of adsorbates. Our results
indicate that when the scattering region is fully covered by homogeneous
adsorbates, i.e., $n_i=1$, a transmission gap opens around the Dirac point and
its width is almost proportional to $\gamma^2$. In particular, two conductance
plateaus of $G=2e^2/h$ appear in the vicinity of the electron energy $E=\pm
\gamma$. When the scattering region is partially covered by homogeneous
adsorbates ($0<n_i<1$), the transmission gap still survives around the Dirac
point even at low $n_i$, and its width is firstly increased by $n_i$ and then
declined by further increasing $n_i$; whereas the conductance decreases with
$n_i$ in the regime of low $n_i$ and increases with $n_i$ in the regime of high
$n_i$. While in the presence of disordered adsorbates whose on-site energies
are random variables characterized by the disorder degree, the transmission gap
disappears at low $n_i$ and reappears at relatively high $n_i$. Furthermore,
the transmission ability of the ZGNR device can be enhanced by the adsorbate
disorder when the disorder degree surpasses a critical value, contrary to the
localization picture that the conduction of a nanowire becomes poorer with
increasing the disorder degree. The physics underlying these transport
characteristics is discussed. Our results are in good agreement with
experiments.

15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom