Browsing by Author "Kono, Y"

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    Low-energy excitations and ground-state selection in the quantum breathing pyrochlore antiferromagnet Ba3Yb2Zn5O11
    (American Physical Society (APS), 2016-06-01) Haku, T; Kimura, K; Matsumoto, Y; Soda, M; Sera, M; Yu, DH; Mole, RA; Takeuchi, T; Nakatsuji, S; Kono, Y; Sakakibara, T; Chang, LJ; Masuda, T
    We study low-energy excitations in the quantum breathing pyrochlore antiferromagnet Ba3Yb2Zn5O11 by a combination of inelastic neutron scattering (INS) and thermodynamical property measurements. The INS spectra are quantitatively explained by spin-12 single-tetrahedron model having XXZ anisotropy and Dzyaloshinskii-Moriya interactions. This model has a twofold degeneracy of the lowest-energy state per tetrahedron and well reproduces the magnetization curve at 0.5 K and heat capacity above 1.5 K. At lower temperatures, however, we observe a broad maximum in the heat capacity around 63 mK, demonstrating that a unique quantum ground state is selected due to extra perturbations with an energy scale smaller than the instrumental resolution of INS. ©2024 American Physical Society. All rights reserved.