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arXiv · 2102.07808

Importance of dynamic lattice effects for crystal field excitations in quantum spin ice candidate Pr$_2$Zr$_2$O$_7$

Yuanyuan Xu·Huiyuan Man·Nan Tang·Santu Baidya·Hongbin Zhang·Satoru Nakatsuji·David Vanderbilt·Natalia Drichko
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Abstract

Pr$_2$Zr$_2$O$_7$ is a pyrochlore quantum spin-ice candidate. Using Raman scattering spectroscopy we probe crystal electric field excitations of Pr$^{3+}$, and demonstrate the importance of their interactions with the lattice. We identify a vibronic interaction with a phonon that leads to a splitting of a doublet crystal field excitation at around 55~meV. We also probe a splitting of the non-Kramers ground state doublet of Pr$^{3+}$ by observing a double line of the excitations to the first excited singlet state $E^0_g \rightarrow A_{1g}$. We show that the splitting has a strong temperature dependence, with the doublet structure most prominent between 50~K and 100~K, and the weight of one of the components strongly decreases on cooling. We suggest a static or dynamic deviation of Pr$^{3+}$ from the position in the ideal crystal structure can be the origin of the effect, with the deviation strongly decreasing at low temperatures.

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Yuanyuan Xu, Huiyuan Man, Nan Tang, Santu Baidya, Hongbin Zhang, Satoru Nakatsuji, David Vanderbilt, Natalia Drichko. 2021-02-15. Importance of dynamic lattice effects for crystal field excitations in quantum spin ice candidate Pr$_2$Zr$_2$O$_7$. https://doi.org/10.1103/physrevb.104.075125

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