Diffusion Enhancement by Spontaneous Formation of Frenkel Defects in NaCl-type High-Entropy Materials

High-entropy materials (HEMs) are attracting attention due to their exceptional properties, such as enhanced mechanical toughness, irradiation resistance, ionic conductivity, and thermoelectric performance. Although diffusion is an important phenomenon as it is closely related to these physical properties of materials, there is a lack of understanding of the mechanisms of diffusion due to the complexity of the atomic interactions in HEMs. Here, we investigates diffusion mechanisms in PbTe-based HEMs AgInSnPbBiTe5, focusing on the role of indium (In). Molecular dynamics simulations reveal that In+ spontaneously forms Frenkel defect and enhancing diffusion not only of In+ but also other cations. Furthermore, as a result of enhanced diffusion, short-range order is formed by structural relaxation. This insight not only enhances comprehension of HEMs diffusion mechanisms but also develops HEMs with properties such as self-healing from damage and high ion permeability, advancing the field of material science.