I was just studying for an exam for my Greek culture class, and realized that if Herodotus is the only historian who documented the events, not only does he often exaggerate, but he may be missing events that were more important on the Persian side of the war.
So are there any Persian writers who documented the events of the war? And how trustworthy would their accounts be?
I am not an expert or have any knowledge in the field but since I am looking for the answer to the same question for a paper my AskHistorians search turned up this thread that should answer your question. It is 2 years old but I doubt a Persian source material has been discovered in the last 2 years.