Symmetry lowering on the field-induced commensurate phase in CeRhIn${}_5$

Temperature dependence of the ${}^{115}$In-NMR spectra of CeRhIn${}_5$ is studied with the external magnetic fields 10${}^{\circ }$ off the [100] and [001] axes. Our detailed analyses confirm that the AFM3 phase breaks the four-fold spin symmetry with the commensurate ordering vector of $Q=(0.5,0.5,0.25)$. Based on the observation of anistropic hyperfine fields, we also propose the symmetry lowering of the electronic structure in the AFM3 phase.