By. Gu et al., ELECTRONIC STATES AND MAGNETOTRANSPORT IN QUANTUM WAVE-GUIDES WITH NONUNIFORM MAGNETIC-FIELDS, Physical review. B, Condensed matter, 56(20), 1997, pp. 13434-13441
The electronic states and magnetotransport properties of quantum waveg
uides (QW's) in the presence of nonuniform magnetic fields perpendicul
ar to the QW plane are investigated theoretically. It is found that th
e magnetoconductance of those structures as a function of Fermi energy
exhibits stepwise variation or square-wave-like oscillations, dependi
ng on the specific distributions (both in magnitude and direction) of
nonuniform magnetic fields in QW's. We have investigated the dual magn
etic strip structures and three magnetic strip structures. The charact
er of the magnetotransport is closely related to the effective magneti
c potential and the energy-dispersion spectrum of electron in the stru
ctures. It is found that dispersion relations seem to be combined by d
ifferent sets of dispersion curves that belong to different individual
magnetic subwaveguides. The magnetic effective potential leads to the
coupling of states and the substantial distortion of the original dis
persion curves at the interfaces in which the abrupt change of magneti
c fields appears. Magnetic scattering states are created. Only in some
three magnetic strip structures, these scattering states produce the
dispersion relations with oscillation structures superimposed on the b
ulk Landau levels. It is the oscillatory behavior in dispersions that
leads to the occurrence of square-wave-like modulations in conductance
.