\documentclass[a4paper, oneside, 10pt]{article}
\usepackage[unicode]{hyperref}
\usepackage[utf8x]{inputenc}
\usepackage[english]{babel}
\usepackage{fixltx2e}
\date{\today}
\title{}
\author{}
\usepackage[utf8x]{inputenc}
\begin{document}



\subsection{\texorpdfstring{Phosphorene \& Phosphorene Oxides}{Phosphorene  Phosphorene Oxides}}
\label{sec:phosphorene__phosphorene_oxides}


\url{https://en.wikipedia.org/wiki/Phosphorene} is a single layer of black phosphorous, recently
synthesized. This new two-dimensional layered material has attracted much attention due to its potential usage for electronic or optoelectronic devices. Because of a lone pair of electrons on each phosphorous atom,  however, pristine phosphorene may be extremely reactive with air, especially with oxygen, and thus the oxidation of phosphorene would be unavoidable during synthesis and/or fabrication processes unless they were done in a vacuum environment.

\subsubsection{\texorpdfstring{Structural properties of phosphorene oxides}{Structural properties of phosphorene oxides}}
\label{sec:structural_properties_of_phosphorene_oxides}


Due to the existence of a lone pair of electrons on each P atom, 
phosphorene can be easily oxidized. At first, we have investigated 
the structural stability of PO\textsubscript{\emph{x}} with 0\textless \emph{x}\textless 1. 
For every given 0\textless \emph{x}\textless 1 of PO\textsubscript{\emph{x}}, diverse configurations 
are considered and optimized to find its equilibrium structure to know 
whether such a phosphorene oxide can be formed or not.



\subsubsection{\texorpdfstring{Strain effects on electronic properties of phosphorene oxides}{Strain effects on electronic properties of phosphorene oxides}}
\label{sec:strain_effects_on_electronic_properties_of_phosphorene_oxides}


As \emph{x} increases in PO\textsubscript{\emph{x}}, the electronic properties of
phosphorene oxides changes. We found an intriguing phenomenon that at
around 16\% uniaxial tensile strain, PO (with \emph{x}=1) becomes a metal
with a modified Dirac cone at the gamma point in its Brillouin zone.



\begin{center}
\line(1,0){250}
\end{center}



\end{document}
