Press Release

Double dome structure of the Bose-Einstein condensation in diluted S = 3/2 quantum magnets

Release:Mar 10, 2023 Update:Mar 10, 2023
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Graduate student Yoshito Watanabe, Professor Takahisa Arima, Associate Professor Yusuke Tokunaga, Associate Professor Kenichiro Hashimoto and Professor Takasada Shibauchi of the Department of Advanced Materials Science in the Graduate School of Frontier Sciences led the research project.


Bose-Einstein condensation (BEC) in quantum magnets, where bosonic spin excitations condense into ordered ground states, is a realization of BEC in a thermodynamic limit. Although previous magnetic BEC studies have focused on magnets with small spins of S ≤ 1, larger spin systems potentially possess richer physics because of the multiple excitations on a single site level. Here, we show the evolution of the magnetic phase diagram of S = 3/2 quantum magnet Ba2CoGe2O7 when the averaged interaction J is controlled by a dilution of magnetic sites. By partial substitution of Co with nonmagnetic Zn, the magnetic order dome transforms into a double dome structure, which can be explained by three kinds of magnetic BECs with distinct excitations. Furthermore, we show the importance of the randomness effects induced by the quenched disorder: we discuss the relevance of geometrical percolation and Bose/Mott glass physics near the BEC quantum critical point.   


Publication:    Nature Communications
Title:    Double dome structure of the Bose-Einstein Condensation in Diluted S=3/2 Quantum Magnet
Authors:    Y. Watanabe, A. Miyake, M. Gen, Y. Mizukami, K. Hashimoto, T. Shibauchi, A. Ikeda, M. Tokunaga, T. Kurumaji, Y. Tokunaga, T. Arima 
DOI:    10.1038/s41467-023-36725-4

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