2014/04/30 by J. A. Crosse · 6 citations
Chemistry · Materials Science · Physics and Astronomy · #2D Materials and Applications #Band gap #Bilayer #Bilayer graphene #Carbon Nanotubes in Composites #Chemistry #Composite material #Condensed matter physics #Conductivity #Graphene #Graphene research and applications #Layer (electronics) #Materials science #Membrane #Nanotechnology #Optoelectronics #Physics #Ribbon #Semiconductor #Semimetal #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.90.235403
published in Physical Review B 90(23) (American Physical Society) · Updated to journal version with new title and revised figures. 8 pages, 6 figures
openalex publication_date 2014/12/01 · arxiv created 2014/12/03 · arxiv updated 2014/12/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Intrinsic bilayer graphene is a gapless semimetal. Under the application of a bias field it becomes a semiconductor with a direct band gap that is proportional to the applied field. Under a layer-asymmetric strain (where the upper layer undergoes compression and the lower layer tension or vice versa) we find that the band gap of a biased bilayer graphene ribbon becomes indirect and, for higher strains, becomes negative, returning the material to its original semimetal state. As a result, the conductivity of the ribbon increases and can be almost an order of magnitude larger than that of the intrinsic unbiased material---a change that can be induced with a strain of only \ensuremath≈2--3%. The conductivity is proportional to the applied strain and the magnitude of the effect is tunable with the bias field. Such layer-asymmetric strains can be achieved by bending, with forces on the order of \ensuremath≈1\phantom\rule0.28em0exnN, resulting in a layer-asymmetric strain of \ensuremath≈1%. This electromechanical effect has a wide potential for application in the areas of nanoforce microscopy and pressure sensing on the atomic scale.