我正在尝试将两个pgfplots图形（均已width=95\textwidth设置）底部对齐，并绘制一个边界框。设置这两个subfigure图形的相关代码：
\begin{figure}
\centering
\begin{subfigure}[b]{0.5\linewidth}
\centering
\input{./texfig/FN_plot}
\end{subfigure}%
\hfill
\begin{subfigure}[b]{0.5\linewidth}
\centering
\input{./texfig/FN_plot_hot}
\end{subfigure}
\caption{FN plot. Protrusion height $h=\SI{20}{nm}$. Real (apex) $\beta = 11.8$. On the left, $T_{\text{ambient}} = \SI{300}{K}$ and on the right $T_{\text{ambient}} = \SI{800}{K}$.}
\label{fig:FN_plot}
\end{figure}
结果是：
。
为什么它们没有底部对齐？显然，边界框没有重叠。通过减小图形的宽度，我可以让它们对齐，但它们之间的空白太多了。有什么想法吗？
编辑：删除所有不相关的内容，以下是.tex文件：
FN_plot.tex
\begin{tikzpicture}
\begin{groupplot}[group style={group size=1 by 2, vertical sep=1.3cm}]
\nextgroupplot[
width=0.8\linewidth,
xmin = 0.00125, xmax = 0.00135,
ymin =-24.15, ymax = -23.85,
]
\nextgroupplot[
width=0.95\textwidth,
xmin = 0, xmax = 0.05,
ymin =-200, ymax = -20,
ytick = {-20,-60,...,-220},
xtick = {0,0.01,...,0.04},
xlabel={$1/E$ $\left[(\si{MV/m})^{-1}\right]$},
ylabel={$\ln{(I/E^2)}$ $\left[\si{A.m^2.MV^{-2}}\right]$},
legend pos = north east,
legend cell align = left,
legend style = {draw=none,fill=none}]
\end{groupplot}
\draw (current bounding box.south west) rectangle (current bounding box.north east);
\end{tikzpicture}
和
FN_plot_hot.tex
\begin{tikzpicture}[declare function={Inf=inf;}]
\begin{axis}[
width=0.95\textwidth,
xmin = 0, xmax = 0.05,
ymin =-200, ymax = -20,
ytick = {-20,-60,...,-220},
xtick = {0,0.01,...,0.04},
xlabel={$1/E$ $\left[(\si{MV/m})^{-1}\right]$},
%ylabel={$\ln{(I/E^2)}$ $\left[\si{A.m^2.MV^{-2}}\right]$},
yticklabels={,,},
legend pos = north east,
legend cell align = left,
legend style = {draw=none,fill=none}]
\end{axis}
\draw (current bounding box.south west) rectangle (current bounding box.north east);
\end{tikzpicture}
结果是
答案1
您可以使用groupplot来一次性绘制所有三个图。只需使用
\nextgroupplot[hide axis]%2
对于第二个图，这样它就不会被绘制。这是一个示例。
\documentclass{article}
\usepackage{pgfplots,subcaption,siunitx}
\pgfplotsset{compat=1.12}
\usepgfplotslibrary{groupplots}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture}[shorten >=4pt,shorten <=4pt]
\begin{groupplot}[group style={group size=2 by 2},
height=3.5cm,width=3.5cm,/tikz/font=\small]
\nextgroupplot%1
\addplot coordinates {(0,1) (1,0)};
\nextgroupplot[hide axis]%2
%\addplot coordinates {(0,1) (1,0)};
\nextgroupplot%3
\addplot coordinates {(0,1) (1,0)};
\nextgroupplot%4
\addplot coordinates {(0,1) (1,0)};
\end{groupplot}
\end{tikzpicture}
\caption{FN plot. Protrusion height $h=\SI{20}{nm}$. Real (apex) $\beta = 11.8$. On the left, $T_{\text{ambient}} = \SI{300}{K}$ and on the right $T_{\text{ambient}} = \SI{800}{K}$.}
\label{fig:FN_plot}
\end{figure}
\end{document}
通过你的方法它就变成了（这也适用于\input）
\documentclass{article}
\usepackage{pgfplots,subcaption,siunitx}
\pgfplotsset{compat=1.12}
\usepgfplotslibrary{groupplots}
\begin{document}
\begin{figure}
\centering
\centering
\begin{subfigure}[b]{0.5\linewidth}
\centering
\begin{tikzpicture}[shorten >=4pt,shorten <=4pt]
\begin{groupplot}[group style={group size=1 by 2},
height=3.5cm,width=3.5cm,/tikz/font=\small]
\nextgroupplot%1
\addplot coordinates {(0,1) (1,0)};
\nextgroupplot%2
\addplot coordinates {(0,1) (1,0)};
\end{groupplot}
\end{tikzpicture}
\end{subfigure}%
\hfill
\begin{subfigure}[b]{0.5\linewidth}
\centering
\begin{tikzpicture}[shorten >=4pt,shorten <=4pt]
\begin{axis}[height=3.5cm,width=3.5cm,/tikz/font=\small]
\addplot coordinates {(0,1) (1,0)};
\end{axis}
\end{tikzpicture}
\end{subfigure}%
\caption{FN plot. Protrusion height $h=\SI{20}{nm}$. Real (apex) $\beta = 11.8$. On the left, $T_{\text{ambient}} = \SI{300}{K}$ and on the right $T_{\text{ambient}} = \SI{800}{K}$.}
\label{fig:FN_plot}
\end{figure}
\end{document}
通过你的文件，我得到了这个
