Spin and e-e interactions in quantum dots: Leading order corrections to universality and temperature effects
| dc.creator | Usaj, Gonzalo | |
| dc.creator | Baranger, Harold U. | |
| dc.date | 2002-03-05 | |
| dc.date.accessioned | 2026-07-07T06:31:31Z | |
| dc.date.available | 2026-07-07T06:31:31Z | |
| dc.description | We study the statistics of the spacing between Coulomb blockade conductance peaks in quantum dots with large dimensionless conductance g. Our starting point is the ``universal Hamiltonian''--valid in the g->oo limit--which includes the charging energy, the single-electron energies (described by random matrix theory), and the average exchange interaction. We then calculate the magnitude of the most relevant finite g corrections, namely, the effect of surface charge, the ``gate'' effect, and the fluctuation of the residual e-e interaction. The resulting zero-temperature peak spacing distribution has corrections of order Delta/sqrt(g). For typical values of the e-e interaction (r_s ~ 1) and simple geometries, theory does indeed predict an asymmetric distribution with a significant even/odd effect. The width of the distribution is of order 0.3 Delta, and its dominant feature is a large peak for the odd case, reminiscent of the delta-function in the g->oo limit. We consider finite temperature effects next. Only after their inclusion is good agreement with the experimental results obtained. Even relatively low temperature causes large modifications in the peak spacing distribution: (a) its peak is dominated by the even distribution at kT ~ 0.3 Delta (at lower T a double peak appears); (b) it becomes more symmetric; (c) the even/odd effect is considerably weaker; (d) the delta-function is completely washed-out; and (e) fluctuation of the coupling to the leads becomes relevant. Experiments aimed at observing the T=0 peak spacing distribution should therefore be done at kT<0.1 Delta for typical values of the e-e interaction. | |
| dc.description | 15 pages, 4 figures | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0203074 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0203074 | |
| dc.identifier | Phys. Rev. B 66, 155333 (2002) | |
| dc.identifier | doi:10.1103/PhysRevB.66.155333 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/98629 | |
| dc.subject | Mesoscale and Nanoscale Physics | |
| dc.title | Spin and e-e interactions in quantum dots: Leading order corrections to universality and temperature effects | |
| dc.type | text |