Theoretical study on the resistive switching characteristics of Ag doped TiO2
Resistive random access memory(RRAM)is a type of non-volatile memory.Compared to traditional memory,resistive ran-dom access memory has achieved significant breakthroughs in both read and write speed and storage performance,and is recognized as a new generation of mainstream memory.However,resistive random access memory based on metal oxides such as TiO2 still has un-clear resistive mechanism.The first principles based on density functional theory were used to study the resistive switching characteris-tics of Ag doped TiO2,and the results revealed that the formation energy and surface energy in the four directions of[001],[110],[011],and[111]are all negative,making it the easiest to deposit and form a surface.The maximum potential energy surface value in the[011]and[111]direction is the largest,making it easy for charges to accumulate.The critical potential energy surface is also the largest,making it easy to form conductive filament.Simultaneously,the diffusion barrier in[011]and[111]direction is the min-imum,making it easy to form conductive channels.The bandgap in the[011]and[111]directions is significantly smaller than that in the[001]and[110]directions,and there is a significant orbital hybridization,which makes it easy to form conductive filament in specific directions.The effective mass of electron and hole in[011][111]directions is about 2/3 of that in[001][110]directions,and the mobility is about 1.5-2 times that in the[001][110]direction,therefore,it is easier to form conductive filaments under the action of an external electric field.The conductivity increases rapidly in the[011]and[111]directions,which are ideal directions to achieve resistive switching characteristics.The research results can provide theoretical guidance for improving the performance of resis-tive random access memory based on TiO2.
resistance random access memory(RRAM)conductive filamentTiO2diffusion barrierfirst principle
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