title: Hover effect on IconButton in Material-UI
body: <p><a href="https://i.stack.imgur.com/lsYHX.png" rel="noreferrer">IconButton Hover</a></p>
  
  <p>This is an iconButton from Material-UI that I am using. As you can see there is a slight grey border around the icon when you hover on it. What is the property to disable this? I have not found it in Material-UI docs, and I need to get rid of this grey hover feature. </p>
  
  <p>Code:</p>
  
  <pre><code>&lt;IconButton&gt;
      &lt;BackButton /&gt;
  &lt;/IconButton&gt;
  </code></pre>