Field-induced valence fluctuation in YbB$_{12}$
| Autor: | Kurihara, R., Miyake, A., Tokunaga, M., Ikeda, A., Matsuda, Y. H., Miyata, A., Gorbunov, D. I., Nomura, T., Zherlitsyn, S., Wosnitza, J., Iga, F. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 103, 115103 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.103.115103 |
| Popis: | We performed high-magnetic-field ultrasonic experiments on YbB$_{12}$ up to 59 T to investigate the valence fluctuations in Yb ions. In zero field, the longitudinal elastic constant $C_{11}$, the transverse elastic constants $C_{44}$ and $\left( C_{11} - C_{12} \right)/2$, and the bulk modulus $C_\mathrm{B}$ show a hardening with a change of curvature at around 35 K indicating a small contribution of valence fluctuations to the elastic constants. When high magnetic fields are applied at low temperatures, $C_\mathrm{B}$ exhibits a softening above a field-induced insulator-metal transition signaling field-induced valence fluctuations. Furthermore, at elevated temperatures, the field-induced softening of $C_\mathrm{B}$ takes place at even lower fields and $C_\mathrm{B}$ decreases continuously with field. Our analysis using the multipole susceptibility based on a two-band model reveals that the softening of $C_\mathrm{B}$ originates from the enhancement of multipole-strain interaction in addition to the decrease of the insulator energy gap. This analysis indicates that field-induced valence fluctuations of Yb cause the instability of the bulk modulus $C_\mathrm{B}$. Comment: 15 pages, 11 figures |
| Databáze: | arXiv |
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