How do I change the size of a matrix within a matrix?

Question

I am trying to make the inner matrix the same size as the 0, i.e. the large matrix should have two equally sized components, a 0 and a small matrix (1,0).

Here is my MWE

\documentclass[amsmath,amssymb,12pt,eqsecnum]{revtex4}
\usepackage[a4paper]{geometry}
\linespread{1}
\usepackage[breaklinks, colorlinks, citecolor=blue]{hyperref}
\usepackage{slashed}
\usepackage{gensymb}
\usepackage{simplewick}
\usepackage{feynmp-auto}
\usepackage[pdftex]{graphicx}
\begin{document}

\begin{pmatrix} 
            0 \\
            {\begin{pmatrix} 
                    1 \\ 0 
            \end{pmatrix}} 
\end{pmatrix}
\end{document}

Answer 1

You can use smallmatrix:

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\[
\begin{pmatrix} 
 0 \\
 \left(\begin{smallmatrix} 
  1 \\ 0 
 \end{smallmatrix}\right)
\end{pmatrix}
\]

\end{document}

This doesn't require resources other than amsmath, so I made the example as short as possible.