As explained in the last section, an HEA mainly contains random solid solution and/or ordered solid solution. Their matrices could be regarded as whole-solute matrices. In HEAs, those whole-solute matrices diffusion vacancy are surrounded by different element atoms, and thus have a specific lattice potential energy (LPE). This large fluctuation of LPE between lattice sites leads to low-LPE sites can serve as traps and hinder atomic diffusion. This leads to the sluggish diffusion effect.