CPM Seminar

Cavity Spintronics

Can-Ming Hu

University of Manitoba

Cavity Spintronics [1] (also known as Spin Cavitronics and Cavity Magnonics) is an emerging interdisciplinary field that studies and utilize the strong coupling between cavity photons with collective spin excitations such as magnons [2-10]. Via the quantum physics of spin-photon entanglement on the one hand, and classical electrodynamic coupling on the other, magnon-photon coupling connects some of the most exciting modern physics, such as quantum information and quantum optics, with one of the oldest science on the earth, the magnetism.

This talk aims to provide an introduction to this new frontier of condensed matter physics. Starting with the intuitive example of coupled harmonic oscillators, the talk introduces the general concepts of coherent and dissipative coupling, based on which two streams of current research will be presented: (i) The development of diverse cavity-mediated coupling and transducing techniques for quantum and spintronic applications, — all utilize the hybrid nature of a quasi-particle induced by coherent magnon-photon coupling [6]. (ii) The study of dissipative magnon-photon coupling govern by a non-Hermitian Hamiltonian, which is related to the physics of exceptional point [7], level attraction [8], and synchronized spin-photon coupling [9], — all these may create important applications such as topological energy transfer, quantum sensing, and nonreciprocal photon transmission [10]. Highlighted results will be presented in the broad context of brilliant work done by a few leading groups in the past 5 years.

[1] C.-M. Hu, Phys. in Canada, 72, No. 2, 76 (2016).
[2] H. Huebl, et al., Phys. Rev. Lett. 111, 127003 (2013).
[3] Y. Tabuchi, Y. et al. Phys. Rev. Lett. 113, 083603 (2014).
[4] X. Zhang, et al., Phys. Rev. Lett. 113, 156401 (2014).
[5] L. Bai, et al., Phys. Rev. Lett. 114, 227201 (2015).
[6] M. Harder and C.-M. Hu, Solid State Physics, 69, 47-121 (2018), Academic Press.
[7] D. Zhang, et al., Nat. Commun. 8, 1368 (2017).
[8] M. Harder, et al., Phys. Rev. Lett., 121, 137203 (2018).
[9] V. L. Grigoryan, K. Shen, and K. Xia, Phys. Rev. B 98, 024406 (2018).
[10] Yipu Wang, et al., Phys. Rev. Lett., (2019), in print.