Dephasing time of disordered two-dimensional electron gas in modulated magnetic fields
Abstract
The dephasing time of disordered two-dimensional electron gas in modulated magnetic field H=\{0,0,H/cosh2[(x-x0)/δ]\} is studied. In the weak inhomogeneity limit where δ is much larger than the linear size of the sample, τ-1φ is proportional to H. In the strong inhomogeneity limit, it is shown that the dependence is quadratic, τ-1φ=D(e/ħc)2H2δ2. In the intermediate regime, a crossover between these two limits occurs at Hc=(ħc/4e)δ-2. It is demonstrated that the origin of the dependence of τφ on H lies in the nature of corresponding single-particle motion. A semiclassical Monte Carlo algorithm is developed to study the dephasing time, which is of a qualitative nature but efficient in uncovering the dependence of τφ on H for arbitrarily complicated magnetic-field modulation. Computer simulations support analytical results. The crossover from linear to quadratic dependence is then generalized to the situation with magnetic field modulated periodically in one direction with zero mean, and it is argued that this crossover can be expected for a large class of modulated magnetic fields.
- Publication:
-
Physical Review B
- Pub Date:
- March 2002
- DOI:
- 10.1103/PhysRevB.65.115303
- arXiv:
- arXiv:cond-mat/0203059
- Bibcode:
- 2002PhRvB..65k5303W
- Keywords:
-
- 73.23.-b;
- 73.20.Fz;
- 73.63.-b;
- Electronic transport in mesoscopic systems;
- Weak or Anderson localization;
- Electronic transport in nanoscale materials and structures;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 8 pages, 2 figures