Upper bound on the window of density occupied by microemulsion phases in two-dimensional electron systems

Fuente: arXiv
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Main Authors: Joy, Sandeep, Skinner, Brian
Format: Preprint
Published: 2023
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author Joy, Sandeep
Skinner, Brian
author_facet Joy, Sandeep
Skinner, Brian
contents In two-dimensional electronic systems, direct first-order phase transitions are prohibited as a consequence of the long-range Coulomb interaction, which implies a stiff energetic penalty for macroscopic phase separation. A prominent proposal is that any direct first-order transition is instead replaced by a sequence of ``microemulsion" phases, in which the two phases are mixed in patterns of mesoscopic domains. In this note, we comment on the range $Δn$ of average electron density that such microemulsion phases may occupy. We point out that, even without knowing the value of a phenomenological parameter associated with surface tension between the two phases, one can place a fairly strong upper bound on the value of $Δn$. We make numerical estimates for $Δn$ in the case of the Fermi liquid to Wigner crystal transition and find $Δn$ to be on the order of $10^7$\,cm$^{-2}$. This value is much smaller than the width of the phase transition observed in experiments, suggesting that disorder is a more likely explanation for the apparent broadening of the transition.
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id arxiv_https___arxiv_org_abs_2309_03961
institution arXiv
publishDate 2023
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spellingShingle Upper bound on the window of density occupied by microemulsion phases in two-dimensional electron systems
Joy, Sandeep
Skinner, Brian
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
In two-dimensional electronic systems, direct first-order phase transitions are prohibited as a consequence of the long-range Coulomb interaction, which implies a stiff energetic penalty for macroscopic phase separation. A prominent proposal is that any direct first-order transition is instead replaced by a sequence of ``microemulsion" phases, in which the two phases are mixed in patterns of mesoscopic domains. In this note, we comment on the range $Δn$ of average electron density that such microemulsion phases may occupy. We point out that, even without knowing the value of a phenomenological parameter associated with surface tension between the two phases, one can place a fairly strong upper bound on the value of $Δn$. We make numerical estimates for $Δn$ in the case of the Fermi liquid to Wigner crystal transition and find $Δn$ to be on the order of $10^7$\,cm$^{-2}$. This value is much smaller than the width of the phase transition observed in experiments, suggesting that disorder is a more likely explanation for the apparent broadening of the transition.
title Upper bound on the window of density occupied by microemulsion phases in two-dimensional electron systems
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2309.03961