To this end, mobility values obtained using the SERTA under ABINIT are compared with those acquired using AMSET, as illustrated in Figure . It is found that the agreement between the two SERTA results is close, and this indicates that POP scattering is potentially overestimated in AMSET for CuI due to the SERTA. Therefore, we propose that the mobility limit in CuI is determined in the low concentration regime by IBTE e-ph scattering and in the high concentration regime by ionised impurity scattering.