Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
笠原 成*; Shi, H. J.*; 橋本 顕一郎*; 利根川 翔*; 水上 雄太*; 芝内 孝禎*; 杉本 邦久*; 福田 竜生; 寺嶋 孝仁*; Nevidomskyy, A. H.*; et al.
Nature, 486(7403), p.382 - 385, 2012/06
被引用回数:399 パーセンタイル:99.22(Multidisciplinary Sciences)The electron nematicity, which break rotational symmetry of the crystal lattice, has been recently observed in high- superconductors. In iron-pnictides, it has been associated with the tetragonal-to-orthorhombic structural transition at
, and the observations has been limited in the orthorhombic phase or in the tetragonal phase under uniaxial strain. In this investigation we provide magnetic torque measurements, a thermodynamic evidence which clearly shows the development of nematicity well above
and the persistence in the nonmagnetic superconducting regime. Combined with synchrotron X-ray measurements, our results identify two distinct temperatures-one at
, signifying a true nematic transition, and the other at
(
), which we show to be not a true phase transition, but rather what we refer to as a "meta-nematic transition", in analogy to the well-known metamagnetic transition in the theory of magnetism.