Electric-field-induced controlled motion of polar meron in epitaxially strained BiFeO3 thin film

Using first principles-based effective Hamiltonian, electric field-controlled (reversible and repeatable) motion of spontaneously created topological charge particle across the thickness of a (001)-oriented epitaxially strained BiFeO3 3 thin film is studied. It is shown that the electric field below a critical value moves this topological particle reversibly and gradually up and down across the film thickness, while the field higher than the critical value moves it from the bottom of the thin film straight to the top and back under alternating positive and negative fields. These field-controlled mobile topological charge particles are shown to be chiral and have topological charge corresponding to a meron. These electric-field-controlled meron motions can provide inspiration for the future of topological entity-based ferroelectric memory devices.