Bilayer Graphene as a Platform for Bosonic Symmetry-Protected Topological States

Zhen Bi, Ruixing Zhang, Yi Zhuang You, Andrea Young, Leon Balents, Chaoxing Liu, Cenke Xu

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Bosonic symmetry protected topological (BSPT) states, the bosonic analogue of topological insulators, have attracted enormous theoretical interest in the last few years. Although BSPT states have been classified by various approaches, there is so far no successful experimental realization of any BSPT state in two or higher dimensions. In this paper, we propose that a two-dimensional BSPT state with U(1)×U(1) symmetry can be realized in bilayer graphene in a magnetic field. Here the two U(1) symmetries represent total spin Sz and total charge conservation, respectively. The Coulomb interaction plays a central role in this proposal - it gaps out all the fermions at the boundary, so that only bosonic charge and spin degrees of freedom are gapless and protected at the edge. Based on the above conclusion, we propose that the bulk quantum phase transition between the BSPT and trivial phase, which can be driven by applying both magnetic and electric fields, can become a "bosonic phase transition" with interactions. That is, only bosonic modes close their gap at the transition, which is fundamentally different from all the well-known topological insulator to trivial insulator transitions that occur for free fermion systems. We discuss various experimental consequences of this proposal.

Original languageEnglish (US)
Article number126801
JournalPhysical Review Letters
Volume118
Issue number12
DOIs
StatePublished - Mar 20 2017

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graphene
platforms
symmetry
insulators
proposals
fermions
magnetic fields
conservation
degrees of freedom
interactions
analogs
electric fields

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Bi, Zhen ; Zhang, Ruixing ; You, Yi Zhuang ; Young, Andrea ; Balents, Leon ; Liu, Chaoxing ; Xu, Cenke. / Bilayer Graphene as a Platform for Bosonic Symmetry-Protected Topological States. In: Physical Review Letters. 2017 ; Vol. 118, No. 12.
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Bilayer Graphene as a Platform for Bosonic Symmetry-Protected Topological States. / Bi, Zhen; Zhang, Ruixing; You, Yi Zhuang; Young, Andrea; Balents, Leon; Liu, Chaoxing; Xu, Cenke.

In: Physical Review Letters, Vol. 118, No. 12, 126801, 20.03.2017.

Research output: Contribution to journalArticle

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