PhD interview: Why in particular us?
Don't overthink this. Tell the truth! &quot;Your group is the best!&quot; (... and I want to be with the best)...
Yes, if you can make some incidental remarks about how/why you know that their group is &quot;the best&quot;... and in what field, precisely... that would be good. Not just &quot;gee whiz! Gosh!&quot;, but something a bit substantive.
I'd think departments/groups would want to hear from prospects that those prospects appreciate the expertise of the group/department/whatever. Otherwise it's really silly cold-calling. (When I (in the U.S., in math) get cold-call emails from people who're manifestly using a uniform template about &quot;Dear Sir, I've studied and admire your research&quot;, with no details pertaining to me (either in the form-of-address or anything else) it's easy to hit &quot;delete&quot;.