Origin of positive magnetoresistance in small-amplitude unidirectional lateral superlattices

TL;DR

This study investigates the origins of positive magnetoresistance in small-period unidirectional lateral superlattices, revealing that drift velocity from incomplete cyclotron orbits, rather than streaming orbits, primarily causes PMR.

Contribution

It provides a quantitative analysis showing that drift velocity from incomplete cyclotron orbits is the main contributor to PMR, challenging previous assumptions about streaming orbits' role.

Findings

Streaming orbits contribute only a small fraction to PMR.

The inflection point of magnetoresistance indicates the limiting magnetic field of streaming orbits.

Drift velocity from incomplete cyclotron orbits is the dominant cause of PMR.

Abstract

We report quantitative analysis of positive magnetoresistance (PMR) for unidirectional-lateral-superlattice samples with relatively small periods (a=92-184 nm) and modulation amplitudes (V_0=0.015-0.25 meV). By comparing observed PMR's with ones calculated using experimentally obtained mobilities, quantum mobilities, and V_0's, it is shown that contribution from streaming orbits (SO) accounts for only small fraction of the total PMR. For small V_0, the limiting magnetic field B_e of SO can be identified as an inflection point of the magnetoresistance trace. The major part of PMR is ascribed to drift velocity arising from incompleted cyclotron orbits obstructed by scatterings.