I was trying to achieve that, If someone opens the URL /login then It should open the /login/index.php file. and it requires that multiviews needs to be enabled, I found the below options
1.Adding in the .htacces
<IfModule mod_negotiation.c>
Options MultiViews
</IfModule>
Add the multiview option to your apache conf file, like below
<Directory /var/www/sites/foo/> Options +FollowSymLinks +MultiViews +Indexes DirectoryIndex index.php AddType application/x-httpd-php .php
but these solutions didn't work.