Strain Control and Layer-Resolved Switching of Negative Capacitance in BaTiO3/SrTiO3 Superlattices
Abstract
Negative capacitance in BaTiO3/SrTiO3 superlattices is investigated by Monte Carlo simulations in an atomistic effective Hamiltonian model, using fluctuation formulas for responses to the local macroscopic field that incorporates depolarizing fields. We show epitaxial strain can tune the negative capacitance of the BaTiO3 ferroelectric layer and the overall capacitance of the system over a broad temperature range. In addition, we predict and explain an original switching of the negative capacitance from the BaTiO3 layer to the SrTiO3 layer at low temperatures for intermediate strains. Our results indicate how the diffusive character of the multidomain transition in these superlattices improves their viability for capacitance applications.
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