A1 Journal article (refereed)
Flat-band superconductivity in periodically strained graphene : mean-field and Berezinskii–Kosterlitz–Thouless transition (2020)

Peltonen, T. J., & Heikkilä, T. T. (2020). Flat-band superconductivity in periodically strained graphene : mean-field and Berezinskii–Kosterlitz–Thouless transition. Journal of Physics: Condensed Matter, 32(36), Article 365603. https://doi.org/10.1088/1361-648X/ab8b9d

JYU authors or editors

Publication details

All authors or editorsPeltonen, Teemu Juhani; Heikkilä, Tero T.

Journal or seriesJournal of Physics: Condensed Matter



Publication year2020


Issue number36

Article number365603

PublisherInstitute of physics

Publication countryUnited Kingdom

Publication languageEnglish


Publication open accessNot open

Publication channel open access

Publication is parallel published (JYX)https://jyx.jyu.fi/handle/123456789/68731

Publication is parallel publishedhttps://arxiv.org/abs/1910.06671


In the search of high-temperature superconductivity one option is to focus on increasing the density of electronic states. Here we study both the normal and s-wave superconducting state properties of periodically strained graphene, which exhibits approximate flat bands with a high density of states, with the flatness tunable by the strain profile. We generalize earlier results regarding a one-dimensional harmonic strain to arbitrary periodic strain fields, and further extend the results by calculating the superfluid weight and the Berezinskii–Kosterlitz–Thouless (BKT) transition temperature T BKT to determine the true transition point. By numerically solving the self-consistency equation, we find a strongly inhomogeneous superconducting order parameter, similarly to twisted bilayer graphene. In the flat-band regime the order parameter magnitude, critical chemical potential, critical temperature, superfluid weight, and BKT transition temperature are all approximately linear in the interaction strength, which suggests that high-temperature superconductivity might be feasible in this system. We especially show that by using realistic strain strengths T BKT can be made much larger than in twisted bilayer graphene, if using similar interaction strengths. We also calculate properties such as the local density of states that could serve as experimental fingerprints for the presented model.


Free keywordsBCS theory; flat bands; graphene; strain engineering; superconductivity

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Reporting Year2020

JUFO rating2

Last updated on 2024-03-04 at 21:26