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arXiv · 0909.2175

Many-body effects on the $ρ_{xx}$ ringlike structures in two-subband wells

Gerson J. Ferreira·Henrique J. P. Freire·J. Carlos Egues
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Abstract

The longitudinal resistivity $ρ_{xx}$ of two-dimensional electron gases formed in wells with two subbands displays ringlike structures when plotted in a density--magnetic-field diagram, due to the crossings of spin-split Landau levels (LLs) from distinct subbands. Using spin density functional theory and linear response, we investigate the shape and spin polarization of these structures as a function of temperature and magnetic-field tilt angle. We find that (i) some of the rings "break" at sufficiently low temperatures due to a quantum Hall ferromagnetic phase transition, thus exhibiting a high degree of spin polarization ($\sim 50 $%) within, consistent with the NMR data of Zhang \textit{et al.} [Phys. Rev. Lett. {\bf 98}, 246802 (2007)], and (ii) for increasing tilting angles the interplay between the anticrossings due to inter-LL couplings and the exchange-correlation (XC) effects leads to a collapse of the rings at some critical angle $θ_c$, in agreement with the data of Guo \textit{et al.} [Phys. Rev. B {\bf 78}, 233305 (2008)].

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Gerson J. Ferreira, Henrique J. P. Freire, J. Carlos Egues. 2010-03-09. Many-body effects on the $ρ_{xx}$ ringlike structures in two-subband wells. https://doi.org/10.1103/physrevlett.104.066803

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