A parity-breaking electronic nematic phase transition in the spin-orbit coupled metal Cd 2 Re 2 O 7

A nonlinear peek into electronic symmetry Strong interactions among electrons in some materials can cause them to assume configurations that are less symmetric than the underlying crystal lattice. These so-called electronic nematic states usually have inversion symmetry, but theorists have predicted that in metals with strong spin-orbit coupling, the inversion symmetry can be lost. Harter et al. teased out the symmetry of the electronic order in the compound Cd 2 Re 2 O 7 (see the Perspective by Dodge). They found that a known structural transition in this material is a consequence of another, previously hidden electronic order that breaks inversion symmetry. Science , this issue p. 295 ; see also p. 246