使用 pgfplot 进行绘图

Question

我想绘制所附图像pgfplot

MWE（我遇到了问题y-axis）：

\documentclass\[border=5pt\]{standalone}
\usepackage{pgfplots}
\pgfplotsset{width=7cm, compat=1.13}
\usepackage{amsmath,amssymb}
\begin{document}
\begin{tikzpicture}
  \begin{axis} \[  
  xlabel={$\langle \phi\rangle$}, 
  ylabel={$E$},
  axis x line= center,
  axis y line= center, %left, right, bottom, 
  xtick= \empty,
  ytick= \empty,
  xticklabel=\empty,
  yticklabel=\empty,
     \]   % axis lines=center
  \addplot\[mark=none,  red,   ultra thick\] {20 * x^2 + x^4 - 100};
  \end{axis}
\end{tikzpicture}
\end{document}]