Did this graphene result really overturn a physics law?

The law is a useful relationship between electrical and heat conduction in ordinary metals under particular conditions. It is not a rule that every material must follow in every situation. A measured departure, even a striking one, can show where the law’s assumptions stop working without making the law useless or disproving physics.

So I’d treat “overturned” as headline language unless the research itself makes that broader claim. The interesting question is what conditions produced the difference and whether the measurements support the stated size of it.

I’d separate the experimental result from the dramatic framing. The claim about a factor of 200 needs context: which temperatures and measurements were compared, how uncertainty was handled, and what the reference prediction was. Without those details, the number alone doesn’t tell you how sweeping the result is.

Also, the idea that electrons can behave collectively in a material is not the same as saying the laws of physics stopped applying. It would mean the material is behaving in a regime where a simple transport relation may not describe it well.

Short version, a surprising exception can be important without being a demolition job. I’d look for the actual research paper and see whether its authors say the law fails generally, or report a specific departure in a carefully controlled graphene setup. Those are very different claims.