Holy heck. Me too, I got all the way to here getting increasingly confused by the discussion (didn't help that the top comment was from a magnets PhD, which you'd expect in discussion of superconductors, not of semiconductors).

Okay, so this is just semiconductors, which are the boring kind of conductors - still more interesting than regular conductors, but less interesting than train conductors.

Oh wow, I had the same misread and the same gut reaction.

Yep. This has interesting magnetic properties.

In magnetic materials, you must calculate separately the current with spin up and spin down and there ara meny interesting applications. My favorite is[1] https://en.wikipedia.org/wiki/Giant_magnetoresistance

[1] Was. Because it has used for hard disks (see the applications section). Now SSD ruins the interesting anecdote.