• February 3, 2026

  • 4:00 PM (CST): Dynamics of Polar Vortex Crystallization in Ultrathin Ferroelectric Films

    • Speaker: Dr. Suyash Rijal (University of Arkansas)

    • Abstract

      • Polar vortex crystals are periodically ordered vortex structures with alternating vorticity that

        emerge in ferroelectric thin films and superlattices at room temperature. These topological states

        arise from a delicate balance among electrostatic, elastic, and gradient energies and are known to

        be highly tunable through external control parameters. Polar vortex crystals exhibit a range of

        intriguing properties, including collective excitations and strong coupling to light, making them

        promising candidates for functional applications. Although collective vortex motion under

        external stimuli has been demonstrated, the dynamical origin of polar vortex formation remained

        unresolved. Using ab initio–based effective Hamiltonian simulations, vortex crystallization is shown to

        originate from the softening of a phonon mode and can be described as a Z2 × SU(1) symmetrybreaking transition from a vortex-liquid-like state to an ordered vortex crystal. In addition, resonant

        switching of the vortex crystal orientation driven by mid-infrared laser excitation is predicted

        through the activation of collective modes. These results clarify the dynamical nature of polar

        vortices and establish connections with other modulated states of matter, such as spin spirals in

        magnetic systems.