Abstract
In this study, we report results of the high-pressure Hall coefficient measurements in the putative topological Kondo insulator up to 37 GPa. Below 10 GPa, our data reveal that 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 . 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 becomes metallic and magnetic at , both the peak and the resistance plateau disappear simultaneously. Our results indicate that the peak is a fingerprint to diagnose the presence of a metallic surface state in . The high-pressure magnetic state of is robust to 180 GPa, and no evidence of superconductivity is observed in the metallic phase.
- Received 8 October 2019
- Accepted 28 February 2020
DOI:https://doi.org/10.1103/PhysRevB.101.125116
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