arXiv subjects

M. Gokcedag

Publications and source records attributed to M. Gokcedag.

3 recordsLinked to original sources

arXiv1998

Changing the Electronic Spectrum of a Quantum Dot by Adding Electrons

The temperature dependence of Coulomb blockade peak height correlation is used to investigate how adding electrons to a quantum dot alters or "scrambles" its electronic spectrum. Deviations from finite-temperature random matrix theory with an unchanging spectrum indicate spectral scrambling after a small number of electrons are added. Enhanced peak-to-peak correlations at low temperature are observed. Peak height statistics show similar behavior in several dot configurations despite significant differences in correlations.

cond-mat.mes-hall↗

arXiv1998

Conductance Peak Distributions in Quantum Dots at Finite Temperature: Signatures of the Charging Energy

We derive the finite temperature conductance peak distributions and peak-to-peak correlations for quantum dots in the Coulomb blockade regime assuming the validity of random matrix theory. The distributions are universal, depending only on the symmetry class and the temperature measured in units of the mean level spacing, $Δ$. When the temperature is comparable to $Δ$ several resonances contribute to the same conductance peak and we find significant deviations from the previously known $T \ll Δ$ distributions. In contrast to the $T \ll Δ$ case, these distributions show a strong signature of the charging energy and charge quantization on the dot.

cond-mat.mes-hall↗

arXiv1994

Mesoscopic Spin-Magnetism

We investigate the spin-magnetism of mesoscopic metallic grains. In the average response of an ensemble of grains there are corrections to macroscopic behaviour due to both spectral fluctuations and electron-electron interactions. These corrections are a non-linear function of the magnetic field. Their temperature dependence is calculated numerically and analytically. An experiment is proposed to measure the unknown interaction coupling constant in the cooper channel. For a single sample the magnetization is found to fluctuate reproducibly about the mean. These fluctuations directly probe the energy level statistics.

cond-mat↗