Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 13: Graphene: Electronic Properties, Structure and Substrate Interaction I (joint session O/TT)
TT 13.5: Vortrag
Montag, 12. März 2018, 11:30–11:45, MA 043
Effects of bi-axial strain on heterostructure of hBN and graphene — •Francesco Delodovici1, Silvana Botti2, and Giovanni Onida1 — 1Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy — 2Institute of Condensed Matter Theory and Optics Max-Wien-Platz 1 07743 Jena Germany
I will present a theoretical/computational study of the mechanical and electric properties of an heterostructure consisting of graphene superimposed to hexagonal boron nitride (hBN) when external biaxial strain is applied.
As a preliminary case, we consider a free-standing layer of hBN under uniform biaxial strain: we predict new thermodinamically stable configurations and analyze their mechanical properties, to understand whether they could be accessible experimentally. In addition, we characterize their electrical and optical properites, to detect the emergence of radical changes in hBN properties.
Further on, we turn our attention to the effects of equi-biaxial strain on the graphene-hBN heterostructure.
We use ab-initio crystal structure prediction, and more precisely the fixed-volume minima hopping method to sample the configuration space searching for new configurations. We use density functional tight binding methods to obtain energies and forces for structural prediction and DFT to characterize the electric properties of the new phases.