Thematic area: Nanoscale physics

Combined effects of strains and defects on electrical conductivity of graphene
Sahalianov I.Yu.1, Radchenko T.M.2, Tatarenko V.A.2
1Linköping University, 60174 Norrköping, Sweden 
2G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine,
 36 Academician Vernadsky Boulevard, 03142 Kyiv, Ukraine
E-mails: isagal@ukr.net, tarad@imp.kiev.ua, tatar@imp.kiev.ua

As for all crystalline solids, the presence of a certain amount of disorder in graphene, — the thinnest known material nicknamed as a “miracle material” due to its superior electronic and mechanical properties, — is dictated by the second law of thermodynamics. Defects play a role of disorder and are always present in graphene samples due to the imperfection of the fabrication processes. Implementing the quantum-mechanical Kubo–Greenwood formalism for numerical calculation of dc conductivity, we demonstrate that the electron transport properties of graphene layer can be tailored through the combined effect of defects (point and line scatterers) and strains (uniaxial tension and shear). Defects and strains are commonly present in graphene due to the features of its growth procedure and when it is applied in devices. Being motivated by two experimental works [1, 2], where authors did not observe the transport gap even at large (22.5% of tensile and 16.7% of shear) deformations, we explain possible reasons with an accentuation on graphene’s strain and defect sensing. The revealed strain- and defect-caused electron–hole asymmetry and anisotropy of conductivity, its non-monotony as a function of deformation suggest perspectives for the strain–defect engineering of electronic and transport properties of graphene and related 2D-materials. 

1.	X. He, L. Gao, N. Tang et al., Appl. Phys. Lett. 104, 243108 (2014).
2.	X. He, L. Gao, N. Tang et al., Appl. Phys. Lett. 105, 083108 (2014).