Dephasing of Electrons by Two-Level Defects in Quantum Dots

Abstract

The electron dephasing time ${\tau }_{\varphi }$ in a diffusive quantum dot is calculated by considering the interaction between the electron and dynamical defects, modelled as two-level system. Using the standard tunneling model of glasses, we obtain a linear temperature dependence of $1/{\tau }_{\varphi }$, consistent with the experimental observation. However, we find that, in order to obtain dephasing times on the order of nanoseconds, the number of two-level defects needs to be substantially larger than the typical concentration in glasses. We also find a finite system-size dependence of ${\tau }_{\varphi }$, which can be used to probe the effectiveness of surface-aggregated defects.

two-column 9 pages

References in corpus (9)

• Large-q asymptotics of the random bond Potts model
• Percolation-type description of the metal-insulator transition in two dimensions
• Low-Temperature Saturation of the Dephasing Time and Effects of Microwave Radiation on Open Quantum Dots
• Zero-Point Fluctuations and the Quenching of the Persistent Current in Normal Metal Rings
• On the relationship between the noise-induced persistent current and dephasing rate
• Persistent Current in Normal Metals
• Notes on Decoherence at Absolute Zero
• Non-Gaussian distribution of nearest-neighbour Coulomb peak spacings in metallic single electron transistors
• Persistent current in metals with a large dephasing rate

Cited by in corpus (3)

• Is weak temperature dependence of electron dephasing possible?
• Dephasing by two-level systems at zero temperature by unitary evolution
• Transient electric current through an Aharonov-Bohm ring after switching of a Two-Level-System