Journal Article Low-Energy Excitations and Ground State Selection in Quantum Breathing Pyrochlore Antiferromagnet Ba3Yb2Zn5O11

Haku, T.  ,  Kimura, K.  ,  Matsumoto, Y.  ,  Soda, M.  ,  Sera, M.  ,  Yu, D.  ,  Mole, R. A.  ,  Takeuchi, T.  ,  Nakatsuji, S.  ,  Kono, Y.  ,  Sakakibara, T.  ,  Chang, L.-J.  ,  Masuda1, T.

2016-06-21 , American Physical Society
We study low energy excitations in the quantum breathing pyrochlore antiferromagnet Ba3Yb2Zn5O11 by combination of inelastic neutron scattering (INS) and thermodynamical properties measurements. The INS spectra are quantitatively explained by spin-1/2 single-tetrahedron model having XXZ anisotropy and Dzyaloshinskii-Moriya interaction. This model has a two-fold degeneracy of the lowest-energy state per tetrahe- dron 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 quan- tum ground state is selected due to extra perturbations with energy scale smaller than the instrumental resolution of INS.
UTokyo Research掲載「新しいスピン状態を絶対零度付近にて発見」 URI:
UTokyo Research "New spin state discovered near absolute zero" URI:

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