Point-contact Andreev-reflection spectroscopy of thin-flake superconductors under pressure using diamond anvil cell

Thin-flake superconducting materials are interesting because their superconducting properties can be very sensitive to thickness. While hydrostatic pressure has been demonstrated to be an effective way of tuning bulk superconductors, the analogous study on thin superconductors has been limited due to technical challenges. Recently, some of us have developed a methodology for magnetotransport measurement of thin, cleavable materials using a diamond anvil cell. Here, we use the same diamond anvil cell technique to conduct point-contact Andreev-reflection spectroscopy measurement on thin-flake materials under pressure, offering the opportunity for obtaining spectroscopic information. In this presentation, we will describe our methodology and the challenges we encountered during our point-contact spectroscopy measurements. Furthermore, we will validate the feasibility of this avenue by presenting the temperature-dependent superconducting gap values fitting results of our point-contact spectroscopy measurement on a FeSe thin flake under different pressures. We argue that our methodology provides a conceptually simple tool for a detailed examination of thin superconductors under pressure.