Anisotropic magnetic excitations from single-chirality antiferromagnetic state in Ca-kapellasite

Abstract

We present a ${}^{35}$Cl NMR study for spin $S=1/2$ perfect kagome antiferromagnet Ca-kapellasite (CaCu${}_3$(OH)${}_6$Cl${}_2\cdot$0.6H${}_2$O) with a magnetic transition at $T^{\ast }=7.2$ K. The static magnetic structure in the ground state has been determined to be a chirality-ordered $Q=0$ state, which is selected by a finite Dzyaloshinskii-Moriya interaction. The low-energy magnetic excitations in the ordered state are investigated by the nuclear spin-lattice relaxation rate measurement. We detect a weakly temperature dependent contribution in the magnetic fluctuations perpendicular to the kagome plane in addition to the dispersive spin-wave contribution in the kagome plane. The low-energy magnetic excitations from the coplanar spin structure are attributed to the zero mode originating from the flat band in this kagome antiferromagnet.

5 pages, 5 figures

References in corpus (8)

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• Spin waves in the Frustrated Kagome Lattice Antiferromagnet KFe3(OH)6(SO4)2
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• Weak ferromagnetic order breaking the threefold rotational symmetry of the underlying kagomé lattice in CdCu${}_3$(OH)${}_6$(NO${}_3$)${}_2\cdot$H${}_2$O
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Cited by in corpus (3)

• Orbital Magnetic Moment of Magnons
• $\mathbf{q}=0$ long-range magnetic order in centennialite CaCu${}_3$(OD)${}_6$Cl${}_2$$\cdot$0.6D${}_2$O: A spin-1/2 perfect kagome antiferromagnet with $J_1$-$J_2$-$J_d$
• Emergence of Frustrated Short-Range Order above Long-Range Order in the $S=1/2$ Kagome Antiferromagnet CaCu${}_3$(OD)${}_6$Cl${}_2\cdot 0.6$D${}_2$O