Neutron diffraction study of the emergent magnetic phase in the vicinity of a quantum critical point in CeRhAl4Si2 single crystal

At zero field, CeRhAl4Si2 undergoes two successive AFM transitions at TN1 = 14.2 K (incommensurate) and TN2 = 8.4 K (commensurate), respectively. Upon applying a magnetic field, the first-order transition of TN2 is continuously suppressed at the critical field of 5.5 T parallel to the c-axis. On the other hand, the smooth suppression of the second-order transition of TN1 terminates at a tri-critical point of 6.6 T and 4.7 K, with subsequent splitting into two phase-boundary lines revealing a novel M-phase. This phase is further suppressed by the critical field of 7.2T, giving rise to a quantum critical point (QCP). We, therefore, propose the neutron diffraction study on CeRhAl4Si2 single crystal with magnetic field B // c-axis to investigate the field-induced multiple phase transitions with particular attention to the novel phase emerging out of the quantum spin liquid state near the QCP