GPT-4o did hear of a "Hall bar geometry" though and suggested it's a typo. That one does return results on Google as well, and makes sense in context too.

These materials are pretty expensive. Tellurium is currently about $86/kg, tantalum $430/kg, and iridium $140,000/kg:

https://www.dailymetalprice.com/metalpricecharts.php?c=ir&u=...

https://www.metal.com/en/markets/20

But it's a "2d material" so it only takes a tiny atomically thin quantity of these elements to build a detector:

https://news.columbia.edu/news/what-are-2d-materials-and-why...