Lifting the Curtain on Mysterious Hidden Order Theoretical
spectroscopy and computational model reveal hidden ordered state
February 9, 2010 Electrons in complex matter sometimes arrange
themselves into strange patterns, which remain shrouded in
mystery. Finding the organizing principles and classifying their
phases is an important challenge in understanding condensed
matter. One such material is URu2Si2. "URu2Si2 is a man-made
compound based on uranium, which undergoes an unknown phase
transition," said Kristjan Haule of the Center for Materials
Theory at Rutgers University. "Its constituents display
collective behavior that leads to completely new phenomena."
Indeed, URu2Si2 undergoes a definite phase transition at a very
cold temperature of 17 K that is nearly impossible to miss. This
mysterious ordering pattern has resisted more than twenty years
of intensive experimental investigations with the full battery
of tools used in experimental condensed matter physics. It is
called the "hidden order" for lack o