material-design-icons/av/drawable-anydpi-v21/ic_stop_black_24dp.xml

Material Design icons by Google

<vector xmlns:android="http://schemas.android.com/apk/res/android"
        android:width="24dp"
        android:height="24dp"
        android:viewportWidth="24.0"
        android:viewportHeight="24.0">
    <path
        android:fillColor="#FF000000"
        android:pathData="M6,6h12v12H6z"/>
</vector>