Quantum criticality observed in new class of materials

Quantum criticality, the strange electronic state that may be intimately related to high-temperature superconductivity, is notoriously difficult to study. But a new discovery of "quantum critical points" could allow physicists to develop a classification scheme for quantum criticality—the first step toward a broader explanation.

Quantum criticality occurs in only a few composite crystalline materials and happens at absolute zero—the lowest possible temperature in the universe. The paucity of experimental observations of quantum criticality has left theorists wanting in their quest for evidence of possible causes.

The new finding of "quantum critical points" is in a class of iron superconductors known as "oxypnictides" (pronounced OXEE-nick-tydes). The research by physicists at Rice University, Princeton University, China's Zhejiang University and Hangzhou Normal University, France's École Polytechnique and Sweden's Linköping University appears in this month's issue of Nature Materials.