https://tex.stackexchange.com/questions/405576

test.tex

\documentclass{article}
\pagestyle{empty}
\usepackage{pgfplots}
\usepgfplotslibrary{fillbetween}
\usepgfplotslibrary{groupplots}
\usetikzlibrary{calc}

\begin{document}

\begin{figure}
  \centering
  \begin{tikzpicture}

    % =================== Binding energy graph ========================

    \node [anchor=south west] (nodeEb) at (-0.1,-0.1){};

    \node [anchor=south west] (DOS) at (2.2,-0.5){};

    \begin{axis}
      [  % graph position
      at={(nodeEb)},
      ticks = none,
      set layers,
      axis on top,
      axis line style = thick,
      width=7.5cm,
      height=7cm,
      axis lines=center, 
      domain=0:5,
      samples=100,
      xmin=0, xmax=3,
      ymin=0, ymax=8,
      xlabel style={at={(DOS)},anchor=west},
      y label style={at={(axis description cs:-0.1,0.3)},anchor=south},
      xlabel={DOS},
      ylabel={$E_{B}$}
      ]

      % Fermi energy
      \addplot[color=teal, domain=0:5.9,samples=100, name path=fermi]({0.5*(x-4)^(0.5)},{x});

      % Fill under Fermi
      \path[name path=axis] (axis cs:0,3.9) -- (axis cs:0,5.9);
      \addplot [thick, color=teal, fill=teal,]
      fill between[of=fermi and axis,];
    \end{axis}

    \draw [thick,teal] (0,0.5) -- (4,0.5); % Core energy top
    \draw [thick,teal] (0,1.4) -- (3,1.4); % Core energy bottom
    \draw [thick,teal] (0.05,0) -- (0.05,3); % Baseline

    % ======== Kinetic energy graph =========

    \node [anchor=south west] (nodeEk) at (5.7,4.4){}; % Node plot E_k

    % Axis label nodes
    \node (Int) at (7.5,4.22) {};
    \node (Ek) at (5.8,10){};

    % Ek plot
    \begin{axis}
      [  
      at={(nodeEk)},
      ticks = none,
      set layers,
      axis on top,
      axis line style = thick,
      width=5.5cm,
      height=7cm,
      axis lines=center, 
      domain=0:5,
      samples=100,
      xmin=0, xmax=3,
      ymin=0, ymax=8,
      xlabel style={at={(Int)},anchor=west},
      ylabel style={at={(Ek)},anchor=west},
      xlabel={Intensity},
      ylabel={$E_{K}$}
      ]

      % core signals
      \addplot[color=teal,fill=teal, domain=0:4,samples=1000, name path=peak1] ({0.03/pi*(1/(1+4*(x-1))^2)+7/pi*(0.005/(0.005+4*(x-2)^2))},{x});

      % Fermi energy
      \addplot[color=teal, domain=0:7,samples=100, name path=fermi]({0.7*(x-4)^(0.5)/(e^((x-6)/0.1)+1)},{x});

      % Fill under Fermi
      \path[name path=axis] (axis cs:0,3.9) -- (axis cs:0,10);
      \addplot [thick, color=teal, fill=teal,]
      fill between[of=fermi and axis,];
    \end{axis}

    % ======== Supporting lines ==============
    \draw [thick,dashed] (3.1,1.4) -- (9.8,1.4); % Upper core level Eb

    \draw [thick,dashed] (0,4) -- (8,4); % Fermi energy Eb

    \draw [thick] (0,5) -- (3.5,5) -- (5.8,4.53); % E_{Vac}

    \draw [thick,dashed] (8.9,5.9) -- (9.8,5.9); % Upper core level Ek

    \draw [thick,dashed] (5.9,8.55) -- (9.8,8.55); % Fermi energy Ek

    % ======== Arrows =========================

    \draw[thick,<->] (2.2,4.1)--(2.2,4.9); % Surface work function

    \draw [thick,<->] (5.9,4.1) -- (5.9,4.4); % Analyzer work function

    \draw[thick,->] (-0.5,1.7)--(-0.5,0.7); % Binding energy arrow 

    \draw [violet,very thick, decorate, decoration={snake}, ->] (9.2,1.5)--(9.2,5.7); % Photon

    % =========== Text ========================

    \node at (2.5,4.5){$\Phi_{S}$}; % Surface work function

    \node at (6.3,4.22){$\Phi_{A}$}; % Analyzer work function

    \node at (-0.5,4){$E_{F}$}; % E_F Binding energy graph

    \node at (-0.5,5){$E_{V}$}; % Vacuum energy level

    \node at (5.4,8.55){$E_{F}$}; % E_F Kinetic energy graph

    \node at (2.3,3.4){Valence band}; % Valence band

    \node at (4.2,1){Core levels}; % Core levels

    \node at (8.5,2.8){\large $h\nu$}; % Photon

    \node at (2.1,6){\Large \textbf{Sample}}; % Sample text

    \node at (8,9.5){\Large \textbf{Analyzer}}; % Analyzer text

  \end{tikzpicture}
  \caption{Photoemission process}
  \label{fig:photoemission}
\end{figure}

\end{document}