Antiferro Quadrupole Orders in Non-Kramers Doublet Systems

作者：Hattori Kazumasa^*; Tsunetsugu Hirokazu

来源：Journal of the Physical Society of Japan, 2014, 83(3): 034709.

DOI：10.7566/JPSJ.83.034709

We investigate antiferro quadrupole orders in systems with non-Kramers doublet ground state with total angular momentum J = 4 in T-d point group symmetry. We demonstrate that a pure O-2(2) antiferro quadrupole order is impossible in general crystalline-electric field potential and should be accompanied by ferro O-2(0) quadrupole moment. The temperature and magnetic-field phase diagram is obtained by mean-field approximation of intersite quadrupole interactions and the excitation spectrum is analyzed by "spin"-wave approximations. Gapless excitations emerge at the boader of antiferro O-2(2) quadrupole phases under magnetic field. Quadrupole susceptibilities in the antiferro quadrupole ordered state exhibit unusual singularity and especially the uniform quadrupole susceptibility diverges in addition to the staggered ones. These unusual singularities are also realized at the critical field along [111] direction. We also discuss recent experimental results in PrT2X20 (T = Ir, Rh, Ti, V, and X = Zn, Al).

• 出版日期2014-3