Dephasing time of disordered two-dimensional electron gas in modulated magnetic fields

Article

关键词: NEGATIVE MAGNETORESISTANCE;    LOCALIZATION;    SCATTERING;    FILMS;   

DOI  :  10.1103/PhysRevB.65.115303

来源: SCIE

【 摘 要 】

The dephasing time of disordered two-dimensional electron gas in modulated magnetic field H ={0,0,H/cosh(2)[(x-x(0))/delta]} is studied. In the weak inhomogeneity limit where delta is much larger than the linear size of the sample, tau(phi)(-1) is proportional to H. In the strong inhomogeneity limit, it is shown that the dependence is quadratic,tau(phi)(-1)=D(e/(h) over barc)H-2(2) delta(2). In the intermediate regime, a crossover between these two limits occurs at H-c=((h) over barc/4e)delta(-2). It is demonstrated that the origin of the dependence of tau(phi) 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 tau(phi)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.

【 授权许可】

Free