Dephasing in Open Quantum Dots

Abstract

Shape-averaged magnetoconductance (weak localization) is used for the first time to obtain the electron phase coherence time ${\tau }_{\varphi }$ in open ballistic GaAs quantum dots. Values for ${\tau }_{\varphi }$ in the range of temperature T from 0.335 to 4 K are found to be independent of dot area, and are not consistent with the ${\tau }_{\varphi }\propto T^{-2}$ behavior expected for isolated dots. Surprisingly, ${\tau }_{\varphi }(T)$ agrees quantitatively with the predicted dephasing time for disordered two-dimensional electron systems.

9 pages, 4 figures