Can someone explain why a material that is supposed to be conductive imply?

[fellupahill]

(PhysOrg.com) -- The transition-metal monoxide FeO is an archetypal example of a Mott insulator—a material that should conduct electricity under conventional band theories but becomes an insulator when measured, especially at low temperatures—and a major iron-bearing component of the Earth’s interior. Understanding the high-pressure behavior of this material is important for both solid-state physics and Earth science. But despite considerable study over the past 30 years, the origin of the well-known high-pressure-induced cubic-rhombohedral ferroic transition in FeO, which is a distortion of the original cubic structure to that of as rhomboid shape, has been not well understood.

Source.

Can someone explain what this means?

It seems like it would be a big deal if something that should be a conductor, wasn't. But the word "measured" gets me confused. I start think of quantum mechanics, and maybe I am right to do so, but not sure so just a clarification of what's going on here if someone doesn't mind. And please include what this means for our current theories. For example what changes are going to have to be made, if any?

Btw/ I am asking a question, not speculating.

 

[torquil]

Interesting subject! Did you read this?:

http://en.wikipedia.org/wiki/Mott_insulator

There is a link there to some slides which seem quite instructive.