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Hauptverfasser: Kurihara, R., Sato, Y., Miyake, A., Akaki, M., Mitsumoto, K., Hagiwara, M., Kuwahara, H., Tokunaga, M.
Format: Preprint
Veröffentlicht: 2024
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Online-Zugang:https://arxiv.org/abs/2402.13504
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author Kurihara, R.
Sato, Y.
Miyake, A.
Akaki, M.
Mitsumoto, K.
Hagiwara, M.
Kuwahara, H.
Tokunaga, M.
author_facet Kurihara, R.
Sato, Y.
Miyake, A.
Akaki, M.
Mitsumoto, K.
Hagiwara, M.
Kuwahara, H.
Tokunaga, M.
contents We performed high-magnetic-field magnetization, polarization, and ultrasonic measurements in Ba$_2$CuGe$_2$O$_7$ to investigate field-induced multiferroic properties arising from a cross-correlation between electric dipoles and electric quadrupoles in addition to cross-correlation between magnetic dipoles and electric dipoles. Magnetization $M$ shows saturation behavior above 20 T for several magnetic field directions, however, electric polarization $P_c$ exhibits an increase, and elastic constants show a softening above 20 T. Based on quantum states with a crystalline electric field for the $D_{2d}$ point group and $d$-$p$ hybridization between Cu-$3d$ and O-$2p$ electrons, we confirmed that the matrix of an electric dipole $P_z$ was proportional to that of an electric quadrupole $O_{xy}$. Furthermore, considering the spin-orbit coupling of $3d$ electrons and the Zeeman effect, we showed that $P_z$ and $O_{xy}$ simultaneously exhibited field-induced responses. These findings indicate that the orbital degrees of freedom, in addition to the spin degrees of freedom, contribute to the high-field multiferroicity in Ba$_2$CuGe$_2$O$_7$.
format Preprint
id arxiv_https___arxiv_org_abs_2402_13504
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Field-induced electric polarization and elastic softening caused by parity-mixed $d$-$p$ hybridized states with electric multipoles in Ba$_2$CuGe$_2$O$_7$
Kurihara, R.
Sato, Y.
Miyake, A.
Akaki, M.
Mitsumoto, K.
Hagiwara, M.
Kuwahara, H.
Tokunaga, M.
Strongly Correlated Electrons
We performed high-magnetic-field magnetization, polarization, and ultrasonic measurements in Ba$_2$CuGe$_2$O$_7$ to investigate field-induced multiferroic properties arising from a cross-correlation between electric dipoles and electric quadrupoles in addition to cross-correlation between magnetic dipoles and electric dipoles. Magnetization $M$ shows saturation behavior above 20 T for several magnetic field directions, however, electric polarization $P_c$ exhibits an increase, and elastic constants show a softening above 20 T. Based on quantum states with a crystalline electric field for the $D_{2d}$ point group and $d$-$p$ hybridization between Cu-$3d$ and O-$2p$ electrons, we confirmed that the matrix of an electric dipole $P_z$ was proportional to that of an electric quadrupole $O_{xy}$. Furthermore, considering the spin-orbit coupling of $3d$ electrons and the Zeeman effect, we showed that $P_z$ and $O_{xy}$ simultaneously exhibited field-induced responses. These findings indicate that the orbital degrees of freedom, in addition to the spin degrees of freedom, contribute to the high-field multiferroicity in Ba$_2$CuGe$_2$O$_7$.
title Field-induced electric polarization and elastic softening caused by parity-mixed $d$-$p$ hybridized states with electric multipoles in Ba$_2$CuGe$_2$O$_7$
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2402.13504