We studied acoustoelectric (AE) currents in materials that undergo charge density wave (CDW) transitions, induced by a surface acoustic wave (SAW) on a piezoelectric substrate. The polarity and magnitude of the AE current in ${\mathrm{NbSe}}_3$ and $2H\text{−}{\mathrm{TaSe}}_2$ were modulated due to their CDW transitions. We also found that the sign of the AE current depends on the SAW propagation direction with respect to the crystalline axis of the substrate. A phenomenological model assuming strain-modified conductivity can qualitatively account for the significant modulation of the AE current associated with the CDW transition, as well as the SAW propagation orientation dependence. The present results offer a powerful probe for exploring SAW-electron interactions in van der Waals materials, thereby highlighting their potential for advancing the emerging field of straintronics.

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• Acoustic interactions
• Charge density waves
• Straintronics
• Piezoelectrics
• Transition metal dichalcogenides
• Transition metal trichalcogenides
• Classical electromagnetism
• Elastic wave theory
• Surface acoustic wave