Two-dimensional electrons in spatially inhomogeneous magnetic field

Two-dimensional electron gas (2DEG) subjected to a spatially modulated magn etic field exhibits commensurability oscillation of magnetoresistance, anal ysis of which furnishes information on the modulation amplitude. Under a pe riodically modulated magnetic field with zero mean, the resistivity of the 2DEG gains an extra term expressed as Delta rho = AT(2) + C. The temperatur e quadratic term is attributed to electron-electron umklapp scattering, whi le the constant term arises from combined effect of the lateral magnetic su perlattice and random impurities. In the composite Fermion (CF) regime near the half-filling of lowest Landau levels, spatial variation of the electro n density is equivalent to magnetic field variation. Use of a short period lateral superlattice has enabled us to observe the commensurability oscilla tion of the magnetoresistance of CFs near the filling factor nu = 3/2. The positions of the resistance minima are consistent with those calculated by assuming magnetic modulation and fully spin-polarized CFs. (C) 2001 Elsevie r Science B.V. All rights reserved.