In-situ Investigation of Electronic Properties in Yttrium-hydride Prepared at Low Temperature

We report the in-situ investigation of electronic properties in yttrium (Y) hydride nanocontacts using a point-contact spectroscopy (PCS) technique, where hydrogen (H) atoms are absorbed at T ∼ 16 K. When a bias voltage is applied between both sides of Y nanocontacts immersed in liquid H₂, the differential conductance (dI/dV) spectra are changed largely due to H absorption in the nanocontacts. At the applied voltage of 350 mV, the V-shape anomaly appears at around zero bias in the dI/dV spectra. We conclude that the evolution of the spectra from Y metallic signal to V-shape is probably caused by a metal-insulator transition due to the phase transition from YH₂ to YH₃ from the comparison to the results of PCS experiments on Y-H nanocontacts prepared at high temperature.