Hall-coefficient diagnostics of the surface state in pressurized SmB6
Hall-coefficient diagnostics of the surface state in pressurized SmB6
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DOI：
10.1103/physrevb.101.125116
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发表时间：
2019-09
影响因子：
3.7
通讯作者：
Yazhou Zhou;P. Rosa;Jing Guo;Shu Cai;R. Yu;Sheng Jiang;Ke Yang;Aiguo Li;Q. Si;Qi Wu
中科院分区：
文献类型：
--
作者：
Yazhou Zhou;P. Rosa;Jing Guo;Shu Cai;R. Yu;Sheng Jiang;Ke Yang;Aiguo Li;Q. Si;Qi Wu
在这项研究中，我们报告了假定的拓扑近藤绝缘体 $\mathrm{Sm}{\mathrm{B}}_{6}$ 高达 37 GPa 的高压霍尔系数 $({R}_{H})$ 测量结果。在低于 10 GPa 的温度下，我们的数据表明，${R}_{H}(T)$ 在冷却至 20 K 以下时表现出一个突出的峰值。值得注意的是，表面传导占主导地位的温度与 ${R}_{H}(T)$ 中的峰值温度一致。温度相关的电阻和霍尔系数可以通过双通道模型很好地拟合，其中包括金属表面和热激活体态的贡献。当$\mathrm{Sm}{\mathrm{B}}_{6}$在$\ensuremath{\sim}10\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$处变成金属和磁性时，${R}_{H}(T)$峰值和电阻平台同时消失。我们的结果表明，${R}_{H}(T)$ 峰是诊断 $\mathrm{Sm}{\mathrm{B}}_{6}$ 中是否存在金属表面态的指纹。 $\mathrm{Sm}{\mathrm{B}}_{6}$ 的高压磁态在 180 GPa 下具有鲁棒性，并且在金属相中没有观察到超导性的证据。
In this study, we report results of the high-pressure Hall coefficient $({R}_{H})$ measurements in the putative topological Kondo insulator $\mathrm{Sm}{\mathrm{B}}_{6}$ up to 37 GPa. Below 10 GPa, our data reveal that ${R}_{H}(T)$ exhibits a prominent peak upon cooling below 20 K. Remarkably, the temperature at which surface conduction dominates coincides with the temperature of the peak in ${R}_{H}(T)$. The temperature dependent resistance and Hall coefficient can be well fitted by a two-channel model with contributions from the metallic surface and the thermally activated bulk states. When the bulk of $\mathrm{Sm}{\mathrm{B}}_{6}$ becomes metallic and magnetic at $\ensuremath{\sim}10\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$, both the ${R}_{H}(T)$ peak and the resistance plateau disappear simultaneously. Our results indicate that the ${R}_{H}(T)$ peak is a fingerprint to diagnose the presence of a metallic surface state in $\mathrm{Sm}{\mathrm{B}}_{6}$. The high-pressure magnetic state of $\mathrm{Sm}{\mathrm{B}}_{6}$ is robust to 180 GPa, and no evidence of superconductivity is observed in the metallic phase.