Strain-tuning of transport gaps and semiconductor-to-conductor phase transition in twinned graphene

[Display omitted] We show, through the use of the Landauer-Büttiker (LB) formalism and a tight-binding (TB) model, that the transport gap of twinned graphene can be tuned through the application of a uniaxial strain in the direction normal to the twin band. Remarkably, we find that the transport gap...

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Bibliographic Details
Published in:Acta materialia 2022-08, Vol.234, p.117987, Article 117987
Main Authors: Arca, F., Mendez, J.P., Ortiz, M., Ariza, M.P.
Format: Article
Language:English
Subjects:
Critical phenomena
Geometrical twinning
Graphene
MATERIALS SCIENCE
Phase transformation
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Summary:[Display omitted] We show, through the use of the Landauer-Büttiker (LB) formalism and a tight-binding (TB) model, that the transport gap of twinned graphene can be tuned through the application of a uniaxial strain in the direction normal to the twin band. Remarkably, we find that the transport gap Egap bears a square-root dependence on the control parameter ϵx−ϵc, where ϵx is the applied uniaxial strain and ϵc∼19% is a critical strain. We interpret this dependence as evidence of criticality underlying a continuous phase transition, with ϵx−ϵc playing the role of control parameter and the transport gap Egap playing the role of order parameter. For ϵxϵc the transport gap closes to zero and the material becomes conductor, which evinces a semiconductor-to-conductor phase transition. The computed critical exponent of 1/2 places the transition in the meanfield universality class, which enables far-reaching analogies with other systems in the same class.
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2022.117987