Dephasing of electrons by two-level defects in quantum dots
Abstract
The electron dephasing time τφ in a diffusive quantum dot is calculated by considering the interaction between the electron and dynamical defects, modeled as two level systems. Using the standard tunneling model of glasses, we obtain a linear temperature dependence of 1/τφ, 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 τφ, which can be used to probe the effectiveness of surface-aggregated defects.
- Publication:
-
Physical Review B
- Pub Date:
- May 2001
- DOI:
- 10.1103/PhysRevB.63.195301
- arXiv:
- arXiv:cond-mat/0011139
- Bibcode:
- 2001PhRvB..63s5301A
- Keywords:
-
- 73.23.-b;
- 72.70.+m;
- 73.20.Fz;
- Electronic transport in mesoscopic systems;
- Noise processes and phenomena;
- Weak or Anderson localization;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- two-column 9 pages