N ov 1 99 7 Microscopic origin of the conducting channels in metallic atomic - size contacts

Microscopic Origin of Conducting Channels in Metallic Atomic-Size Contacts

We present a theoretical approach which allows one to determine the number and orbital character of conducting channels in metallic atomic contacts. We show how conducting channels arise from atomic orbitals with a significant contribution to bands around the Fermi level. Our theory predicts that the number of conducting channels with non-negligible transmission is three for Al and five for Nb ...

What are Landauer’s conduction channels in an atomic-size metallic contact?

Using microfabricated break junctions, we have produced Al and Au contacts consisting of a small number of atoms. These metallic quantum point contacts accomodate a small number of conduction channels. We have determined the individual transmission coefficients in contacts containing up to six conduction channels. The determination is based on a comparison of the highly nonlinear current–voltag...

2 3 N ov 1 99 7 ORIGIN OF PURE SPIN SUPERRADIANCE

X iv : c on d - m at / 9 71 11 36 v 1 1 4 N ov 1 99 7 On Charged

We investigate the existence of stable charged metallic bubbles using the shell correction method. We find that for a given mesoscopic system of n atoms of a given metal and q ≪ n (positive) elementary charges, a metallic bubble turns out to have a lower total energy than a compact spherical cluster, whenever the charge number q is larger than a critical charge number qc. For a magic number (n ...

Chemical Bonding and Charge Distribution at Metallic Nanocontacts

We present results of electronic structure calculations for aluminium contacts of atomic size, based on density functional theory and the local density approximation. Addressing the atomic orbitals at the neck of the nanocontact, we find that the local band structure deviates strongly from bulk fcc aluminium. In particular, hybridization between Al 3s and 3p states is fully suppressed due to di...