Applicability of the macroscopic Becquerel-type model to chiral molecular crystals

Determine whether the macroscopic Becquerel-type model for acoustic magneto-chiral anisotropy accurately describes ultrasound propagation in diamagnetic crystals composed of chiral molecules, in which the lattice building blocks possess intrinsic electronic and vibrational chirality that can couple to ultrasound.

Background

The paper develops and uses a simple macroscopic Becquerel-like model to account for the magnitude and frequency dependence of acoustic magneto-chiral anisotropy (aMChA) observed in α-quartz. The authors then discuss how this model might generalize beyond inorganic chiral crystals.

They highlight a special case of diamagnetic crystals formed by chiral molecules, where the molecular building blocks themselves exhibit electronic and vibrational chirality that could couple to ultrasound, potentially altering the physics captured by the macroscopic model.

References

A special case consists of diamagnetic crystals of chiral molecules, where the lattice building blocks themselves can also have electronic and vibrational chirality, which can couple to ultrasound propagation. It is unclear whether our macroscopic model can provide a good description of this case.

— Observation of acoustic magneto-chiral anisotropy in $α$-quartz  (2604.01013 - Altangerel et al., 1 Apr 2026) in Main text, paragraph beginning "A special case consists of diamagnetic crystals of chiral molecules" (toward the end of the paper)