Sorting Author Contributor Page by Last Name

Is there anyway to do this? I found

function twentyfourteen_list_authors() {
	$contributor_ids = get_users( array(
		'fields'  => 'ID',
		'orderby' => 'post_count',
		'order'   => 'DESC',
		'who'     => 'authors',
	) );

But changing post_count to last_name doesn’t work. Has anybody sorted this out yet? Thanks in advance!