Magnetic structure determination of noncentrosymmetric Kondo lattice antiferromagnet CeIrSi3

CeIrSi3 belongs to the family of noncentrosymmetric heavy-fermion superconductors, which have attracted significant attention for their distinct unconventional superconducting ground state characterized by mixed spin-singlet and spin-triplet pairing symmetry. At ambient pressure, CeIrSi3 exhibits an antiferromagnetic (AFM) ordering at TN=5 K, and becomes superconducting upon suppressing AFM order by pressure with a superconducting Tc ≈ 1.6 K at a Pc=2.5 GPa. In order to understand the nature of 4f-electrons, hard or easy-axis ordering and their role in the superconductivity in CeIrSi3 a knowledge of its detailed magnetic structure is highly desired. Further, we want to test the position of CeIrSi3 on the Doniach phase whether it orders with hard or an easy axis. We therefore propose to carry out neutron diffraction measurements on CeIrSi3 using the WISH diffractometer.

CeIrSi3属于非中心对称重费米子超导体（noncentrosymmetric heavy-fermion superconductors）家族，该类材料因具备以自旋单态-三重态混合配对对称性为核心特征的独特非常规超导基态，受到学界广泛关注。常压条件下，CeIrSi3在奈尔温度TN=5 K时发生反铁磁（antiferromagnetic, AFM）有序；当通过压力抑制反铁磁有序后，其在临界压力Pc=2.5 GPa处进入超导态，超导转变温度Tc≈1.6 K。为阐明CeIrSi3中4f电子的本质、磁有序的易/难轴特性及其在超导性中的作用，亟需获取其精细的磁结构信息。此外，我们计划验证CeIrSi3在多伊奇相（Doniach phase）中的有序轴类型（易轴或难轴）。据此，我们提议利用WISH衍射仪（WISH diffractometer）对CeIrSi3开展中子衍射测量。