Single-atom conductance of Y

Y is a trivalent metal like Al but has one d valence electron instead of one p valence electron in Al. This makes a single-atom contact of Y a suitable playground for investigating how d valence electrons contribute to the single-atom conductance. In this paper, we present the results of our theoretical and experimental studies of the single-atom conductance of Y. We carried out conductance measurements on Y contacts and found that the conductance histogram observed at 4 K exhibits a single broad peak at 1.9G01.9G0. We also calculated the electron transmission through a Y single-atom contact and obtained the total transmission 1.75 at the Fermi level. Both our theoretical and experimental findings consistently indicate that the single-atom conductance of Y lies at (1.8–1.9)G0(1.8–1.9)G0, which is nearly twice as high as that of Al. This increase in the single-atom conductance is due to the second and the third eigenchannels of Y which accomplish higher transmission compared to those of Al. We found that the difference in the contours of sd- and sp-eigenchannels can account for the higher transmission of the sd-eigenchannels.