Valley polarization effects on the localization in graphene Landau levels

Abstract

Effects of disorder and valley polarization in graphene are investigated in the quantum Hall regime. We find anomalous localization properties for the lowest Landau level (LL), where disorder can induce wavefunction delocalization (instead of localization), both for white-noise and gaussian-correlated disorder. We quantitatively identify the contribution of each sublattice to wavefunction amplitudes. Following the valley (sublattice) polarization of states within LLs for increasing disorder we show: (i) valley mixing in the lowest LL is the main effect behind the observed anomalous localization properties, (ii) the polarization suppression with increasing disorder depends on the localization for the white-noise model, while, (iii) the disorder induces a partial polarization in the higher Landau levels for both disorder models.

arXiv comment5 pages, 6 figures, extended version, with 2 new figures added

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• The shape of disorder broadened Landau subbands in graphene
• Edge states in graphene in magnetic fields -- a speciality of the edge mode embedded in the n=0 Landau band
• Disorder-driven splitting of the conductance peak at the Dirac point in graphene
• Valley polarization in graphene-silicene-graphene heterojunction
• Correlated random hopping disorder in graphene at high magnetic fields: Landau level broadening and localization properties
• Splitting of critical energies in the $n$=0 Landau level of graphene
• Current flow in biased bilayer graphene: the role of sublattices
• Inducing a topological transition in graphene nanoribbons superlattices by external strain
• Graphene in the Quantum Hall Regime: Effects of Vacancies, Sublattice Polarization and Disorder