The nonlinear optical absorption in As/GaAs double-graded quantum wells: magnetic field effect and the position-dependent effective mass effectHuan Yu, Zi Zhen, Yi-Sheng Shi, Kang-Xian Guo, E. Feddi, Jian-Hui Yuan and Zhi-Hai ZhangEur. Phys. J. Plus, 136 5 (2021) 555DOI: https://doi.org/10.1140/epjp/s13360-021-01543-4