<研究ノート>鉄系超伝導体BaFe2(As1-xPx)2 におけるネマティック秩序

Abstract

Strongly interacting electrons can exhibit novel collective phases. Among them the electronic nematic phase is perhaps the most surprising as it is a unidirectional self-organized state that breaks the rotational symmetry of the underlying lattice. Here we provide evidence for the electronic nematic ordering in BaFe2(As1-xPx)2 — one of the cleanest iron-based superconductors, by highly sensitive in-plane torque magnetometry and complementary synchrotron X-ray diffraction measurements. Our results show that the nematicity develops well above the tetragonal-orthorhombic transition temperature (TS) and even persists to the nonmagnetic superconducting regime.