I want to list all unique authors that have posts in the current category.

My code (location: wp-content/themes/custom-theme/category.php)

    <div class="container">
    	<div class="row">
    	
    	  <?php if ( have_posts() ) : ?>
    	  
    		<?php while( have_posts() ) : the_author(); ?>
    		
    			<div class="col-md-2 text-center">
    				<?php the_author_meta( 'display_name', 30 ); ?>
    			</div>
    			
    		<?php endwhile; ?>
    
    	  <?php else: ?>
    
    		<p class="text-center">No authors</p>
    
    	  <?php endif; ?>
    	  
    	 </div>
    </div>

This is not giving expected result, can someone help me?