Molecular dynamics simulation of trapping/detrapping mechanisms in α-Al2O3 and MgO lattice

Energy storage and release in dielectric materials can be described on the basis of the charge trapping mechanism. Many experiments have been realized to characterize the charge trapping behavior and thus try to avert dielectric breakdown or flashover occurring beyond a critical concentration of trapped charge. Recently, mirror method experiments have been carried out on single crystals of α-Al₂O₃ and MgO, they have shown two different behaviors: in the case of the α-Al₂O₃ lattice, charges can be trapped but only below a critical temperature of about 240 K, whereas in MgO lattice, charges were not trapped even at very low temperatures. In this paper, molecular dynamics techniques have been used to complete the preceding results with a dynamic approach. Simulations have focused on the trapping/detrapping mechanisms occurring in the range of the pico-second to the femto-second, the time particularly critical in elucidating the difference in behavior of these materials