Abstract
Efficient generation of magnons is highly desirable for magnonics. Here we theoretically investigate the charge-magnon conversion at the interface of topological insulator/antiferromagnetic insulator (AFMI), where the Dirac electrons and the antiferromagnetic magnons are coupled by the fluctuation of s-d exchange field. Our model reveals that the charge-magnon conversion efficiency for uncompensated interface is 2–3 orders higher than that for compensated interface. The conversion is more efficient with smaller magnon gap and larger s-d exchange coupling. We find a significant efficiency enhancement when the thickness of the AFMI is in the two-dimensional regime, where the magnons experience a quantum confinement effect. bilayers are then proposed to be a promising system to realize strong charge-magnon conversion. Our work provides the principles of manipulating charge-magnon conversion and designing efficient charge-magnon conversion structure, which would help to improve the performance of antiferromagnetic magnonics, such as magnon transistor and magnon torque memories.
- Received 6 July 2020
- Revised 5 September 2020
- Accepted 9 September 2020
DOI:https://doi.org/10.1103/PhysRevB.102.115152
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