Spin and conductance-peak-spacing distributions in large quantum dots: a density-functional theory study.
نویسندگان
چکیده
We use spin-density-functional theory to study the spacing between conductance peaks and the ground-state spin of 2D model quantum dots with up to 200 electrons. Distributions for different ranges of electron number are obtained in both symmetric and asymmetric potentials. The even/odd effect is pronounced for small symmetric dots but vanishes for large asymmetric ones, suggesting substantially stronger interaction effects than expected. The fraction of high-spin ground states is remarkably large.
منابع مشابه
Ground-state energy and spin in disordered quantum dots
We investigate the ground-state energy and spin of disordered quantum dots using spin-density-functional theory. Fluctuations of addition energies (Coulomb-blockade peak spacings) do not scale with average addition energy but remain proportional to level spacing. With increasing interaction strength, the even-odd alternation of addition energies disappears, and the probability of non-minimal sp...
متن کاملSpin and e-e interactions in quantum dots: Leading order corrections to universality and temperature effects
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→` 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 ...
متن کاملDensity-functional theory simulation of large quantum dots
Kohn-Sham spin-density functional theory provides an efficient and accurate model to study electronelectron interaction effects in quantum dots, but its application to large systems is a challenge. Here an efficient method for the simulation of quantum dots using density-function theory is developed; it includes the particlein-the-box representation of the Kohn-Sham orbitals, an efficient conju...
متن کاملCoulomb blockade peak spacing fluctuations in deformable quantum dots: a further test to Random Matrix Theory
We propose a mechanism to explain the fluctuations of the ground state energy in quantum dots in the Coulomb blockade regime. Employing the random matrix theory we show that shape deformations may change the adjacent peak spacing distribution from Wigner-Dyson to nearly Gaussian even in the absence of strong charging energy fluctuations. We find that this distribution is solely determined by th...
متن کاملStatistics of Coulomb Blockade Peak Spacings
Distributions of Coulomb blockade peak spacings are reported for large ensembles of both unbroken (magnetic field B 0) and broken (B fi 0) time-reversal symmetry in GaAs quantum dots. Both distributions are symmetric and roughly Gaussian with a width of ,2% 6% of the average spacing, with broad, non-Gaussian tails. The distribution is systematically wider at B 0 by a factor of ,1.2 6 0.1. N...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Physical review letters
دوره 90 2 شماره
صفحات -
تاریخ انتشار 2003