Tellurium vacancy in two-dimensional Si2Te3 for resistive random-access memory

2D materials show exciting prospects in the application of nonvolatile resistive random-access memory (RRAM). Here, by using first-principles calculations based on density functional theory, we demonstrate that the experimentally observed resistive switching behavior in layered Si2Te3 could arise from the formation and diffusion of Te vacancies (VTe). Specifically, we find that VTe0 and VTe2− are the most stable vacancies under both Te-rich/poor growing conditions. Moreover, the interlayer and intralayer diffusion energy barriers of VTe are analyzed by the climbing image nudged elastic band (cNEB) calculation, the results show that VTe with −2 charge is easier to mobile through the lattice. In order to investigate the possibility of effective tuning of the properties of VTe, we apply uniaxial strains along a or b axis of Si2Te3. It is found that the formation energy and diffusion energy barrier of VTe varies upon tensile or compressive strains, pointing out a feasible way to further promote the mobility of Te vacancies in Si2Te3.