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arXiv · 2301.00917

Anomalous circular phonon dichroism in transition metal dichalcogenides

Wen-Yu Shan
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Abstract

A magnetic field can generally induce circular phonon dichroism based on the formation of Landau levels of electrons. Here, we study the magnetization-induced circular phonon dichroism in transition metal dichalcogenides, without forming Landau levels. We find that, instead of the conventional deformation potential coupling, pseudogauge-type electron-phonon coupling plays an essential role in the emergence of the phenomenon. As a concrete example, a large dichroism signal is obtained in monolayer MoTe2 on a EuO substrate, even without considering Rashba spin-orbit coupling. Due to the two-dimensional spin-valley-coupled band structure, MoTe2 shows a reciprocal and nonreciprocal absorption of circularly polarized acoustic phonons upon reversing the direction of phonon propagation and magnetization, respectively. By varying the gate voltage, a tunable circular phonon dichroism can be realized, which paves a way toward different physics and applications of two-dimensional acoustoelectronics.

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Wen-Yu Shan. 2023-01-03. Anomalous circular phonon dichroism in transition metal dichalcogenides. https://doi.org/10.1103/physrevb.105.l121302

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