Kavli Affiliate: Gang Su
| First 5 Authors: YuanDong Wang, Zhen-Gang Zhu, Gang Su, ,
| Summary:
Magnons are electrically neutral bosonic quasiparticles emerging as
collective spin excitations of magnetically ordered materials, and play a
central role in the next-generation spintronics owing to its obviating Joule
heating. A difficult obstacle for quantum magnonics is that the magnons do not
couple to the external electric field directly so that a direct electric
manipulation via bias or gate voltage as in conventional charge-based devices
seems not applicable. In this work, we propose a new mechanism in which magnons
can be excited and controlled by electric field of light directly. Since the
electric field of light can be tuned in a wide and easy way, the proposal is of
great interest in realistic applications. We call it as the magnon spin
photogalvanic effect (SPGE), which comes from five contributions: the Drude,
Berry curvature dipole (BCD), injection, shift, and rectification, with
distinct geometric origins. We further show that the responses to
linearly-polarized or circularly-polarized light are determined by
band-resolved quantum metric or Berry curvature, the two combined together just
comprise of a quantum geometric tensor. The proposed magnon SPGE can be
measured by a characterized topological phase transition. We also discuss a
breathing kagome-lattice model of ferromagnets and suggest possible candidate
materials to implement it.
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