Interaction-driven (quasi-) insulating ground states of gapped electron-doped bilayer graphene

Fuente: arXiv
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Main Authors: Seiler, Anna M., Statz, Martin, Weimer, Isabell, Jacobsen, Nils, Watanabe, Kenji, Taniguchi, Takashi, Dong, Zhiyu, Levitov, Leonid S., Weitz, R. Thomas
Format: Preprint
Published: 2023
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author Seiler, Anna M.
Statz, Martin
Weimer, Isabell
Jacobsen, Nils
Watanabe, Kenji
Taniguchi, Takashi
Dong, Zhiyu
Levitov, Leonid S.
Weitz, R. Thomas
author_facet Seiler, Anna M.
Statz, Martin
Weimer, Isabell
Jacobsen, Nils
Watanabe, Kenji
Taniguchi, Takashi
Dong, Zhiyu
Levitov, Leonid S.
Weitz, R. Thomas
contents Bernal bilayer graphene has recently been discovered to exhibit a wide range of unique ordered phases resulting from interaction-driven effects and encompassing spin and valley magnetism, correlated insulators, correlated metals, and superconductivity. This letter reports on a novel family of correlated phases characterized by spin and valley ordering, observed in electron-doped bilayer graphene. The novel correlated phases demonstrate an intriguing non-linear current-bias behavior at ultralow currents that is sensitive to the onset of the phases and is accompanied by an insulating temperature dependence, providing strong evidence for the presence of unconventional charge carrying degrees of freedom originating from ordering. These characteristics cannot be solely attributed to any of the previously reported phases, and are qualitatively different from the behavior seen previously on the hole-doped side. Instead, our observations align with the presence of charge- or spin-density-waves state that open a gap on a portion of the Fermi surface or fully gapped Wigner crystals. The resulting new phases, quasi-insulators in which part of the Fermi surface remains intact or valley-polarized and valley-unpolarized Wigner crystals, coexist with previously known Stoner phases, resulting in an exceptionally intricate phase diagram.
format Preprint
id arxiv_https___arxiv_org_abs_2308_00827
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Interaction-driven (quasi-) insulating ground states of gapped electron-doped bilayer graphene
Seiler, Anna M.
Statz, Martin
Weimer, Isabell
Jacobsen, Nils
Watanabe, Kenji
Taniguchi, Takashi
Dong, Zhiyu
Levitov, Leonid S.
Weitz, R. Thomas
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Bernal bilayer graphene has recently been discovered to exhibit a wide range of unique ordered phases resulting from interaction-driven effects and encompassing spin and valley magnetism, correlated insulators, correlated metals, and superconductivity. This letter reports on a novel family of correlated phases characterized by spin and valley ordering, observed in electron-doped bilayer graphene. The novel correlated phases demonstrate an intriguing non-linear current-bias behavior at ultralow currents that is sensitive to the onset of the phases and is accompanied by an insulating temperature dependence, providing strong evidence for the presence of unconventional charge carrying degrees of freedom originating from ordering. These characteristics cannot be solely attributed to any of the previously reported phases, and are qualitatively different from the behavior seen previously on the hole-doped side. Instead, our observations align with the presence of charge- or spin-density-waves state that open a gap on a portion of the Fermi surface or fully gapped Wigner crystals. The resulting new phases, quasi-insulators in which part of the Fermi surface remains intact or valley-polarized and valley-unpolarized Wigner crystals, coexist with previously known Stoner phases, resulting in an exceptionally intricate phase diagram.
title Interaction-driven (quasi-) insulating ground states of gapped electron-doped bilayer graphene
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2308.00827