Nonreciprocal Magnons and Symmetry-Breaking in the Noncentrosymmetric Antiferromagnet

Spin Seebeck effect in the polar antiferromagnet α−Cu2V2O7

“…1(b). Nonreciprocal magnons were clearly observed very recently in inelastic neutron scattering measurements [10].In this manuscript, we study a thermal generation effect of spin currents, i.e. the longitudinal SSE [13], in antiferromagnetic α-Cu 2 V 2 O 7 .…”

“…In the proposed spin Hamiltonian [10], there are three important terms to explain the magnetic properties of α-Cu 2 V 2 O 7 . The first term is isotropic exchange interactions.…”

“…The clear observation of the SSE in antiferromagnetic α-Cu 2 V 2 O 7 allows us to test the theoretical models proposed for the antiferromagnetic SSE [16,17]. Using the magnon spin current theory [17] combined with magnetic parameters determined by previous neutron experiments for α-Cu 2 V 2 O 7 [8-10], we demonstrated that temperature and magnetic-field dependences of magnon lifetimes are important for the antiferromagnetic SSE in α-Cu 2 V 2 O 7 |Pt systems.Single crystals of α-Cu 2 V 2 O 7 were grown by a vertical Bridgman method following the previous reports [8][9][10]. …”

“…Single crystals of α-Cu 2 V 2 O 7 were grown by a vertical Bridgman method following the previous reports [8][9][10].…”

Broken symmetries, non-reciprocity, and multiferroicity

“…Recent examples include magneto-chiral dichroism in Ba 2 CoGe 2 O 7 , 33 as well as the opposite spontaneous magnonic Faraday rotation of the counterpropagating spin waves in α-Cu 2 V 2 O 7 . 34 For observations of non-reciprocal effects in optics, one introduces the concept of non-reciprocal directional anisotropy that distinguishes between the two opposite propagation directions and does not depend on the polarization of light (in general, spin or orbital angular momentum). 1,6 Thus, the nonreciprocal directional anisotropy is more narrowly defined than general non-reciprocity, e.g., it excludes the Faraday effect (see Supplementary Information).…”