arXiv subjects

J. S. Harris, Jr

Publications and source records attributed to J. S. Harris, Jr.

3 recordsLinked to original sources

arXiv1999

Coulomb Blockade Fluctuations in Strongly Coupled Quantum Dots

Quantum fluctuations of Coulomb blockade are investigated as a function of the coupling to reservoirs in semiconductor quantum dots. We use fluctuations in the distance between peaks $ΔN$ apart to characterize both the amplitude and correlation of peak motion. For strong coupling, peak motion is greatly enhanced at low temperature, but does not show an increase in peak-to-peak correlation. These effects can lead to anomalous temperature dependence in the Coulomb valleys, similar to behavior ascribed to Kondo physics.

cond-mat.mes-hall↗

arXiv1999

Low-Temperature Saturation of the Dephasing Time and Effects of Microwave Radiation on Open Quantum Dots

The dephasing time of electrons in open semiconductor quantum dots, measured using ballistic weak localization, is found to saturate below ~ 100 mK, roughly twice the electron base temperature, independent of dot size. Microwave radiation deliberately coupled to the dots affects quantum interference indistinguishably from elevated temperature, suggesting that direct dephasing due to radiation is not the cause of the observed saturation. Coulomb blockade measurements show that the applied microwaves create sufficient source drain voltages to account for dephasing due to Joule heating.

cond-mat.mes-hall↗

arXiv1998

Distributions of the Conductance and its Parametric Derivatives in Quantum Dots

Full distributions of conductance through quantum dots with single-mode leads are reported for both broken and unbroken time-reversal symmetry. Distributions are nongaussian and agree well with random matrix theory calculations that account for a finite dephasing time, $τ_ϕ$, once broadening due to finite temperature $T$ is also included. Full distributions of the derivatives of conductance with respect to gate voltage $P(dg/dV_g)$ are also investigated.

cond-mat.mes-hall↗