Judging from trying the links in this rec list (http://deardarkness.tumblr.com/post/22207131595/science-bros-bruce-banner-tony-stark-fanfic-rec) it looks like the author, Ruperts, deleted all those science bros fics from AO3. I was able to find http://archiveofourown.org/users/ruperts/pseuds but they have only two fics up under a different pseud so they might not be the same person. Still, you could try asking them about it in a pressure-free and understanding way?