Computational comparison of the conventional multislice method and the real space multislice method for simulating exit wavefunctions.

The simulation of exit wavefunctions of a TEM sample is carried out by both the conventional multislice (C-MS) method and the real space multislice (RS-MS) method, with a series of different slice thicknesses. Surprisingly, the results calculated by the RS-MS method remain constant to seven significant figures when the slice thicknesses are changed within a wide range, while those calculated by the C-MS method change significantly. From the mathematical point of view, the C-MS method is only a first order approximation of the RS-MS method. Thus, the calculation precision of the RS-MS method is much higher than that of the C-MS method. Or to achieve the same precision, the slice thickness for the RS-MS method can be taken as two orders of magnitude larger than for the C-MS method in the simulation. As a result, the calculation speed for the RS-MS method may be even faster than that for the C-MS method in some cases. For the two advantages stated above, the RS-MS method may be more suitable for precise calculations.