Disentangling the effects of structure and lone-pair electrons in the lattice dynamics of halide perovskites by Caicedo-Dávila, S, Cohen, A, Motti, SG, Isobe, M, McCall, KM, Grumet, M, Kovalenko, MV, Yaffe, O, Herz, LM, Fabini, DH, Egger, DA