Breit interaction, level spacing statistics, and far-infrared absorption in small metal clusters - Yi, Lin; Sheng, Ping
By considering Coulomb and Breit interactions between the electrons, we derive for the first time the variational Breit-Hartree-Fock (BHF) equation. The Breit interaction has two energy scales; one corresponds with the weak magnetic spin-spin and spin-orbit interactions, and the other corresponds with the tensorial exchange potential, which is on the same order as the Coulomb interaction. For small randomly-shaped jellium clusters with up to 276-electrons, we solved numerically the BHF equation. The calculated level spacing statistics is found to differ qualitatively from the Wigner distribution and better correspond with the Poisson distribution. In particular, the prediction of significantly enhanced far-infrared...
(3474884 bytes; application/pdf) - 15-jun-2006
Size dependent single-electron tunneling effect of two-dimensional gold clusters on self-assembled alkylthiol monolayers on Au(111) - Wang, Bing; Xiao, Xudong; Hou, Jianguo; Huang, Xianxiang; Sheng, Ping
Two dimensional (2-D) Au clusters were deposited on the self-assembled alkylthiol monolayer (SAM) by thermal evaporation and their I-V characteristics were studied by STM/STS. The curves show current steps similar to Coulomb blockade and the Coulomb staircase effect with asymmetric behavior. While the zero conductance gap is due to Coulomb blockade, in good agreement with semi-classical theory, the step-plateau behavior with asymmetry in voltage spacing and current increase can be attributed to the effect from internal energy levels.
(900356 bytes; application/pdf) - 15-jun-2006