Squeeze
nitrogen at 2.4 million atmospheres (240 GPa {Giga
Pascals}) and you get
an opaque solid which is a
semiconductor. It remains stable if returned to 1 atmosphere.
"The fact that the major portion of the air has been turned into a
semiconducting solid and brought back to be stable at ambient pressure is
an important breakthrough for us," said team leader Russell Hemley.
Hemley and colleagues Mikhail Eremets, Ho-kwang Mao and Eugene
Gregoryanz performed the research at Carnegie's Geophysical
Laboratory, a core institution of the NSF's Science and Technology Center
for High-Pressure Research.
Source: NSF PR 01-39, 9 May 2001: http://www.nsf.gov/od/lpa/news/press/01/pr0139.htm
It only remains a semiconductor at temperatures below 100 Kelvin:
"Novel nitrogen is a semiconductor", PhysicsWeb, 9 May 2001,
http://physicsweb.org/article/news/05/5/5.
Some questions:
(1) What is the switching speed of the semiconductor?
(2) What can you dope it with to make transistors?
(3) How stable is it? (Maybe that is why the computers go 'Kablam!' in Star Trek!)