Magneto Transport and Quantum Effects in Electron Systems

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The following are the main research accomplishments of this project :(1)Angular dependent magnetoresistance oscillation(ADMRO) effect in organic conductors.Angular dependent oscillatory magnetoresistance has been observed in organic conductors, (BEDT-TTG)_2KHg(SCN)_4 and (BEDT-TTG)_2NH_4Hg(SCN)_4. We have performed precise measurements of the angular dependence by two-axis rotation of samples in high magnetic fields to clarify that the ADMRO in the latter system is a standard one arising form a modulated cylindrical Fermi surface, while that in the latter is attributed to a pair of open Fermi sheet. We have also made a model calculation which reproduced the ADMRO traces of the latter system quantitatively.(2)ADMRO effect in synthetic layred metal --- SbCl_5-intercalated graphiteWe have also observed the ADMRO in intercalated graphite. Analysis of both the ADMRO and the Shubnikov-de Haas effect powerful means of reconstruction of the Fermi surface, which is known to be complex in this system due to zone folding effect and magnetic breakdown effect.(3)ADMRO effect in tailored Fermi surface of GaAs/AlGaAs superlattice.We have designed and fabricated cylindrical Fermi surface in GaAs/AlGaAs superlattice and demonstrated that the ADMRO occurs most distinctly in the out-of-plane resistivity.(4)Magnetotransport in modulated magnetic field.We have theoretically analyzed the effect of one-dimensionally modulated magnetic field on two-dimensional electron gas. We have made an experimental attempt by use of a grid gate made of ferromagnetic substances.