English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report an experimental investigation of fractional quantum Hall effect(FQHE) at the even-denominator Landau level filling factor $\nu$ = 1/2 in veryhigh quality wide GaAs quantum wells, and at very high magnetic fields up to 45T. The quasi-two-dimensional electron systems we study are confined to GaAsquantum wells with widths $W$ ranging from 41 to 96 nm and have variabledensities in the range of $\simeq 4 \times 10^{11}$ to $\simeq 4 \times10^{10}$ cm$^{-2}$. We present several experimental phase diagrams for thestability of the $\nu=1/2$ FQHE in these quantum wells. In general, for a given$W$, the 1/2 FQHE is stable in a limited range of intermediate densities whereit has a bilayer-like charge distribution; it makes a transition to acompressible phase at low densities and to an insulating phase at highdensities. The densities at which the $\nu=1/2$ FQHE is stable are larger fornarrower quantum wells. Moreover, even a slight charge distribution asymmetrydestabilizes the $\nu=1/2$ FQHE and turns the electron system into acompressible state. We also present a plot of the symmetric-to-antisymmetricsubband separation ($\Delta_{SAS}$), which characterizes the inter-layertunneling, vs density for various $W$. This plot reveals that $\Delta_{SAS}$ atthe boundary between the compressible and FQHE phases increases\textit{linearly} with density for all the samples. Finally, we summarize theexperimental data in a diagram that takes into account the relative strengthsof the inter-layer and intra-layer Coulomb interactions and $\Delta_{SAS}$. Weconclude that, consistent with the conclusions of some of the previous studies,the $\nu=1/2$ FQHE observed in wide GaAs quantum wells with symmetric chargedistribution is stabilized by a delicate balance between the inter-layer andintra-layer interactions, and is very likely described by a two-component($\Psi_{311}$) state.

Phase Diagrams for the $\nu$ = 1/2 Fractional Quantum Hall Effect in Electron Systems Confined to Symmetric, Wide GaAs Quantum Wells