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arXiv · 2202.04493

Pressure-induced reemergence of superconductivity in BaIr2Ge7 and Ba3Ir4Ge16 with cage structures

Cuiying Pei·Tianping Ying·Yi Zhao·Lingling Gao·Weizheng Cao·Changhua Li·Hideo Hosono·Yanpeng Qi
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Abstract

The clathrate-like or caged compounds have attracted continuing interest due to their structural flexibility as well as fertile physical properties. Here we report a pressure-induced reemergence of superconductivity in BaIr2Ge7 and Ba3Ir4Ge16, two new caged superconductors with two-dimensional building blocks of cage structures. After suppressing the ambient-pressure superconducting (SC-I) state, a new superconducting (SC-II) state emerges unexpectedly, with Tc increased to a maximum of 4.4 K and 4.0 K for BaIr2Ge7 and Ba3Ir4Ge16, respectively. Combined with high-pressure synchrotron x-ray diffraction and Raman measurements, we propose that the reemergence of superconductivity in the caged superconductors can be ascribed to a pressure-induced phonon softening linked to the cage shrink.

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Cuiying Pei, Tianping Ying, Yi Zhao, Lingling Gao, Weizheng Cao, Changhua Li, Hideo Hosono, Yanpeng Qi. 2022-02-09. Pressure-induced reemergence of superconductivity in BaIr2Ge7 and Ba3Ir4Ge16 with cage structures. https://doi.org/10.1063/5.0088235

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