Small amplitude low-field magnetoresistance oscillation in unidirectional lateral superlattices: Geometric resonance of Bragg-reflected cyclotron orbits
Akira Endo and Yasuhiro Iye
Phys. Rev. B 71 081303 (2005)
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We have uncovered a new class of small amplitude magnetoresistance oscillation in unidirectional lateral superlattice (ULSL). The oscillation is observed in a low-field regime, typically $|B|$$\alt$ 0.03 T, as small undulation on top of well-known positive magnetoresistance background. Positions of maxima of the oscillation shift to lower field side with the increase of the electron concentration $n_e$ roughly proportionally to $n_e$$^{-1/2}$, and also with the increase of period $a$ of ULSL samples. The oscillation is attributed to commensurability between the period $a$ and the width of open orbits originating from the miniband structure.