High-pressure phosphorous

Could be useful for spintronics. Found in teeth and bones as well as in fertilizers and DNA, phosphorus is an insulator at room temperature. However, at very high pressures, a series of phase transitions occur. At 10 GPa, phosphorous becomes metallic and can superconduct at about 10 K. At 262 GPa, it takes on a body-centered-cubic (bcc) crystal structure. Now, Sergey Ostanin of the University of Warwick in the UK and his colleagues have studied the high-pressure phase diagram of phosphorous, and calculated that the bcc crystals achieve superconductivity at slightly higher temperatures, somewhere around 20 K. Furthermore, they found that the bcc phase might be stabilized in thin films grown at ambient pressure on some other bcc material. Such a phosphorous film, perhaps sandwiched between films of iron, might be very useful in spintronics applications. For example, a superconducting spin switch could flip-flop from superconductor to regular conductor depending on the spin state of the iron films. (S. Ostanin et al., Phys. Rev. Lett. 91 , 087002, 2003 http://dx.doi.org/10.1103/PhysRevLett.91.087002 .)