A paper written by the Great Albert on superconductivity in the 20s has been translated into english from german and has appeared in arxiv
http://xxx.sf.nchc.gov.tw/abs/physics/0510251

According to this page, the article is the first authored by Einstein to appear in arxiv
http://physicsweb.org/articles/news/9/11/4/1

all the ideas of the paper are now no cutting edge, but surely can offer good historical context