Uniquely identifying quantum Hall phases in charge neutral graphene

Fuente: arXiv
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Hauptverfasser: An, Jincheng, Murthy, Ganpathy
Format: Preprint
Veröffentlicht: 2024
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author An, Jincheng
Murthy, Ganpathy
author_facet An, Jincheng
Murthy, Ganpathy
contents Charge-neutral graphene in the quantum Hall regime is an example of a quantum Hall ferromagnet in a complex spin-valley space. This system exhibits a plethora of phases, with the particular spin-valley order parameters chosen by the system depending sensitively on the short-range anisotropic couplings, the Zeeman field, and the sublattice symmetry breaking field. A subset of order parameters related to lattice symmetry-breaking have been observed by scanning tunneling microscopy. However, other order parameters, particularly those which superpose spin and valley, are more elusive, making it difficult to pin down the nature of the phase. We propose a solution this problem by examining two types of experimentally measurable quantities; transport gaps and collective mode dispersions. We find that the variation of the transport gap with the Zeeman and sublattice symmetry breaking fields, in conjunction with the number of Larmor and gapless modes, provides a unique signature for each theoretically possible phase.
format Preprint
id arxiv_https___arxiv_org_abs_2412_18179
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Uniquely identifying quantum Hall phases in charge neutral graphene
An, Jincheng
Murthy, Ganpathy
Mesoscale and Nanoscale Physics
Charge-neutral graphene in the quantum Hall regime is an example of a quantum Hall ferromagnet in a complex spin-valley space. This system exhibits a plethora of phases, with the particular spin-valley order parameters chosen by the system depending sensitively on the short-range anisotropic couplings, the Zeeman field, and the sublattice symmetry breaking field. A subset of order parameters related to lattice symmetry-breaking have been observed by scanning tunneling microscopy. However, other order parameters, particularly those which superpose spin and valley, are more elusive, making it difficult to pin down the nature of the phase. We propose a solution this problem by examining two types of experimentally measurable quantities; transport gaps and collective mode dispersions. We find that the variation of the transport gap with the Zeeman and sublattice symmetry breaking fields, in conjunction with the number of Larmor and gapless modes, provides a unique signature for each theoretically possible phase.
title Uniquely identifying quantum Hall phases in charge neutral graphene
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2412.18179