Novel Diamond Anvil Cell for Transport Measurement under High Pressure without Difficult Wiring

High pressure is a promising tool to obtain new functional materials which cannot appear under ambient pressure. For example, the discovery with great surprise of high-transition temperature superconductivity in H₃S at ~200 K was recently reported under 150 GPa [1]. Diamond anvil cell (DAC) is most useful apparatus to generate high pressures, however, the resistivity measurement using DAC is quite difficult because it requires the small sample sizes (< 100 μm) and the hard electrodes. Moreover, an insulating layer should be inserted between the electrodes and a metal gasket, which is also broken by applying pressure. In this study, we focused on the boron-doped metallic diamond [2,3] and undoped diamond as a very hard electrode and an insulating layer, respectively. The resistivity measurements of Fe-based superconductor FeSe and very promising thermoelectric material SnSe single crystals have been demonstrated using the developed device under various pressures, and then the pressure effects were clearly observed.

[1] A. P. Drozdov et al., Nature 525, 73 (2015).
[2] R. Matsumoto et al., Rev. Sci. Instrum. 87, 076103 (2016).
[3] R. Matsumoto et al., Jpn. J. Appl. Phys. 56, 05FC01 (2017).