Pressure-induced superconductivity in quasi-one-dimensional semimetal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Ta</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>PdSe</mml:mi><mml:mn>6</mml:mn></mml:msub></mml:mrow></mml:math>
Haiyang Yang, Yonghui Zhou, Liangyu Li, Zheng Chen, Zhuyi Zhang, Shuyang Wang, Jing Wang, Xuliang Chen, Chao An, Ying Zhou, Min Zhang, Ranran Zhang, Xiangde Zhu, Lili Zhang, Xiaoping Yang, Zhaorong Yang
Abstract
Here we report the discovery of pressure-induced superconductivity in quasi-one-dimensional ${\mathrm{Ta}}_{2}{\mathrm{PdSe}}_{6}$, through a combination of electrical transport, synchrotron x-ray diffraction, and theoretical calculations. Our transport measurements show that the superconductivity appears at a critical pressure ${P}_{\mathrm{c}}\ensuremath{\sim}18.3\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$ and is robust upon further compression up to 62.6 GPa. The estimated upper critical field ${\ensuremath{\mu}}_{0}{H}_{\mathrm{c}2}(0)$ in the pressurized ${\mathrm{Ta}}_{2}{\mathrm{PdSe}}_{6}$ is much lower than the Pauli limiting field, in contrast to the case in its isostructural analogs ${M}_{2}{\mathrm{Pd}}_{\mathrm{x}}{X}_{5}$ $(M=\mathrm{Nb}, \mathrm{Ta}; X=\mathrm{S}, \mathrm{Se})$. Concomitant with the occurrence of superconductivity, anomalies in pressure-dependent transport properties are observed, including sign reversal of Hall coefficient, abnormally enhanced resistance, and dramatically suppressed magnetoresistance. Meanwhile, room-temperature synchrotron x-ray diffraction experiments reveal the stability of the pristine monoclinic structure (space group $C2$/$m$) upon compression. Combined with the density functional theory calculations, we argue that a pressure-induced Lifshitz transition could be the electronic origin of the emergent superconductivity in ${\mathrm{Ta}}_{2}{\mathrm{PdSe}}_{6}$.