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arXiv · 2208.14593

Frequency splitting of chiral phonons from broken time reversal symmetry in CrI$_3$

John Bonini·Shang Ren·David Vanderbilt·Massimiliano Stengel·Cyrus E. Dreyer·Sinisa Coh
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Abstract

Conventional approaches for lattice dynamics based on static interatomic forces do not fully account for the effects of time-reversal-symmetry breaking in magnetic systems. Recent approaches to rectify this involve incorporating the first-order change in forces with atomic velocities under the assumption of adiabatic separation of electronic and nuclear degrees of freedom. In this work, we develop a first-principles method to calculate this velocity-force coupling in extended solids, and show via the example of ferromagnetic CrI$_3$ that, due to the slow dynamics of the spins in the system, the assumption of adiabatic separation can result in large errors for splittings of zone-center chiral modes. We demonstrate that an accurate description of the lattice dynamics requires treating magnons and phonons on the same footing.

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John Bonini, Shang Ren, David Vanderbilt, Massimiliano Stengel, Cyrus E. Dreyer, Sinisa Coh. 2022-08-31. Frequency splitting of chiral phonons from broken time reversal symmetry in CrI$_3$. https://doi.org/10.1103/physrevlett.130.086701

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