2018/05/04 by Zhang, Ming-Hui, Zhang, Ming-Liang
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.1805.01756
For the intrinsic carriers of MAPbBr3, the temperature T dependent mobility μ(T) of behaves like μ∝ T-1/2 in piezoelectric tetragonal phase, μ∝ T-1.4 in non-piezoelectric cubic phase. But for the photo-generated carriers in other halide perovskites ABX3, μ∝ T-3/2 behavior is typical. Due to the strong interaction of carrier with longitudinal optical phonon, in ABX3 the carriers mainly exist as optical polarons. The softness of ABX3 renders it without inversion center in tetragonal phase, which allows piezoelectric effect at low carrier concentration. The variations of μ(T) behavior results from (1) the wave vector dependence of the piezoelectric interaction of polarons with acoustic phonons is different from that of ordinary polaron-acoustic phonon interaction; (2) the residual interaction of polaron with 2 longitudinal optical phonons can be ignored at low temperature, but is important at higher temperature; and (3) the concentration of intrinsic carriers is determined by temperature, while the concentration of photo-generated carriers is determined by the incident flux of photons.