2022 Workshop on Recent Developments in Electronic Structure (ES22) Poster Session

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Author: Bonini, John - Flatiron Institute

Title: Chiral phonons from broken time reversal symmetry in CrI3

Abstract: The conventional computational approach to the study of lattice dynamics from first principles is the calculation of forces on nuclei as a function of the set of static nuclei displacements. Within this approach the resulting nuclear equations of motion are, by construction, time-reversal invariant even for systems that break time reversal symmetry in the electronic sector. In this work we develop a first-principles method for computing nuclear equations of motion which capture time reversal broken lattice dynamics. The resulting forces are then not just dependent on nuclei displacements, but also the set of nuclei velocities. These corrected forces result in a splitting of otherwise degenerate phonon frequencies, and phonon eigenvectors which carry angular momentum even in inversion symmetric systems and at the Gamma point. First principles results are presented for CrI3 where splittings of otherwise degenerate phonons are observed.

Other authors: Ren, Shang (Rutgers University); Vanderbilt, David (Rutgers University); Stengel, Massimiliano (ICMAB-CSIC, ICREA); Dreyer, Cyrus (Stony Brook University, Flatiron Institute); Coh, Sinisa (University of California Riverside)