Ultrafast phononic control of 2D ferroelectricity
Abstract
In this research program, my group and I aim to demonstrate that light-induced vibrations of the crystal lattice can be used to control ferroelectric polarization in layered quantum materials. We will develop a theoretical and computational methodology that allows us to simulate the ultrafast structural dynamics that lead to reversal of 2D ferroelectricity and apply it to a wide variety of materials systems. Ferroelectrics are materials that possess an intrinsic electric dipole moment that can be reversed through the application of an electric field. The different orientations of ferroelectric polarization can be used as the zeros and ones in data processing and storage, and devices based on ferroelectric materials, such as ferroelectric memory, are readily being used. The processing speeds of these devices usually lie on the scale of tens of nanoseconds, limited by the electric field pulses that have to be applied in order to switch the electric dipole moments within the ferroelectric material. In contrast, the fundamental physical timescales that limit ferroelectric reversal are based on the motions of ions within the material, which occur on the order of picoseconds, several orders of magnitude faster than current existing technologies. The development of powerful ultrashort laser pulses in the terahertz spectral range has made the coherent and resonant excitation of crystal lattice vibrations (phonons) possible within the last decade. The coherent motion of the atoms changes the intrinsic geometry of the lattice, which alters the potential-energy landscape seen by the electrons and leads to novel interactions within the material. If the amplitude of the atomic motions becomes large enough, the dynamics of the system is governed by nonlinear interactions between phonons that lead to novel states of matter that are not accessible in equilibrium. In recent years, nearly all studies in the field have focused on bulk materials and, despite a decade of research, no functional phononic switching of ferroelectricity has yet been achieved. Here, we will synthesize concepts from coherent nonlinear lattice dynamics and ferroelectric 2D materials and demonstrate that ferroelectric switching can be achieved through interlayer shear modes that slide individual layers with respect to each other, which we call phononic van der Waals sliding. We will use a combination of microscopic and phenomenological modeling and first-principles calculations based on density functional theory to describe the evolution of structural and polarization degrees of freedom in response to the excitation by ultrashort laser pulses. We will apply this methodology to a wide variety of layered ferroelectrics and identify promising compounds for proof-of-concept devices. This phononic slidetronics approach poses a new paradigm in the control of 2D ferroelectricity that exploits the very fundamental time and length scales of ferroelectric-polarization reversal and possibly lays the physical foundation for a new generation of disruptive technologies.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 24, 2023
- Source ID
- W911NF2310243
Entities
People
- Dominik M Juraschek
Organizations
- Army Contracting Command
- Tel Aviv University
- United States Army