MuSR studies of non-centrosymmetric superconductor NbGe2

The NbGe2 compound crystallizes in a NCS monoclinic structure and is described as a chiral crystal. Previous ZF-MuSR experiment at J-PARC showed the increase of muon spin relaxation rate increase below the superconducting transition temperature. However, it is difficult to get a accurate conclusion due to the sample size and experimental conditions. We propose to perform ZF-MuSR experiment at ISIS to confirm whether TRS breaking exists in the superconducting state of this compound. TF-MuSR experiment is also proposed to study the type-1.5 superconductivity of this compound.

二锗化铌（NbGe₂）以非中心对称（non-centrosymmetric, NCS）单斜晶结构结晶，属于手性晶体。此前在J-PARC开展的零场μ子自旋弛豫（Zero-Field Muon Spin Relaxation, ZF-MuSR）实验显示，其超导转变温度以下的μ子自旋弛豫率有所上升。但受样品尺寸与实验条件限制，难以得到准确结论。本研究拟在ISIS开展零场μ子自旋弛豫实验，以验证该化合物超导态中是否存在时间反演对称性破缺（Time Reversal Symmetry breaking, TRS breaking）；同时拟开展横向场μ子自旋弛豫（Transverse Field Muon Spin Relaxation, TF-MuSR）实验，对其1.5型超导电性进行研究。