First-principles study of conduction through a sodium atomic sheet
Electronic conduction in an atomic sheet is examined theoretically from first principles as an example of a typical two-dimensional system. The conductance per atomic chain, calculated assuming a bias voltage of 0.1 V, is 0.87 G0 for the atomic sheet, which is lower than for the corresponding single chain (1.0 G0; G0 = 2e2/h). The difference is attributed to a reduction of the local density of states around the Fermi level, particularly in the region where the bridge comes into contact with the electrode. [DOI: 10.1380/ejssnt.2006.507]
Recently it has been possible to obtain very pure (99.999+%) metals at a very reasonable cost due to the development of improved large scale purifying processes(1). Studies may now be performed cheaply on pure single crystal specimens of a type approximating the “ideal” specimen assumed in most theories of normal and superconducting metals. In this lecture we summarize the results obtained from experiments involving the superconducting properties (and some normal state properties) of such materials. These results are indicative of the new and interesting phenomena one might observe in very pure single crystal specimens. We will discuss only our own results, for reasons of time limitation and familiarity, although similar data are now found with increasing frequency in the literature.