Fluctuations in quantum dot charging energy

Details Fluctuations in quantum dot charging energy Fluctuations in quantum dot charging energy

1997-09-10

arxiv.org/abs/cond-mat/9709119v1

Physics

Condensed Matter

Mesoscale and Nanoscale Physics

4 pages, 4 .eps figures included with epsf

Scientific paper

10.1016/S0921-4526(98)00104-5

We show that quasi-periodic fluctuations in the charging energy E_C of small, chaotic quantum dots result from strongly scarred states which are the remnant of periodic orbits in the classical confining potential. We perform self-consistent, density functional and spin density functional calculations for the dots used in the recent experimental studies of Sivan et al. [PRL 77, 1123 (1996)]. We directly compute the direct Coulomb matrix elements W_{pq}, screened by the gates, between self-consistent states. We show that diagonal elements (denoted U_p) are uniformly larger than off diagonal elements, resulting in spin polarization of the dot. We show that strongly scarred states, which are quasi-one dimensional, have particularly large values of U_p which causes them to remain, partially occupied, at the Fermi surface as gate voltage V_g is swept and more homogeneous, ``chaotic'' states pass through. We show that ultimate double-filling of these scars results in large upward fluctuations of E_C. In addition, we show that V_g dependence of capacitances and level energies substantially enhances fluctuations in the gate voltage spacing dV_g of Coulomb oscillations, as compared to and distinct from fluctuations in the ``inverse compressibility'' (i.e. E_C). Moreover, these dependences modify the distribution of dV_g fluctuations so that purely upward fluctuations of E_C produce symmetric fluctuations in dV_g. Consequently, gate voltage fluctuations (normalized by the appropriate capacitance ratio) are substantially greater than the single particle level spacing, Delta, but, as we show by direct calculation, their temperature T scaling is consistent with Delta/T and not E_C/T, in complete agreement with experiment.

Affiliated with

Also associated with

No associations

Rating

Fluctuations in quantum dot charging energy does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Fluctuations in quantum dot charging energy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fluctuations in quantum dot charging energy will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1563