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arXiv · 2210.07175

Observation of superconductivity and its enhancement at the charge density wave critical point in LaAgSb$_2$

Kazuto Akiba·Nobuaki Umeshita·Tatsuo C. Kobayashi
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Abstract

We discover superconductivity (SC) in LaAgSb$_2$ at ambient pressure and its close correlation with a charge density wave (CDW) under pressure. The superconducting transition temperature ($T_c$) exhibits a sharp peak at the CDW critical pressure of 3.2 GPa. We demonstrate that the carriers inhabiting the Sb-square net is crucial not only in the formation of CDW but also in SC for their relatively strong electron-phonon coupling (EPC). Furthermore, theoretical EPC strength in pristine LaAgSb$_2$ cannot explain the observed peak with $T_c\sim 1$ K, which indicates that an additional mechanism reinforces SC only around the CDW critical pressure.

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Kazuto Akiba, Nobuaki Umeshita, Tatsuo C. Kobayashi. 2022-10-13. Observation of superconductivity and its enhancement at the charge density wave critical point in LaAgSb$_2$. https://doi.org/10.1103/physrevb.106.l161113

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