Bubbles in graphene - a computational study

Mikkel Settnes,Antti-Pekka Jauho,Jun Lin,Stephen R Power,Dirch H Petersen

doi:10.1088/1742-6596/647/1/012022

Mikkel Settnes, Antti-Pekka Jauho + Show 3 more

Open Access

https://doi.org/10.1088/1742-6596/647/1/012022

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Abstract

Strain-induced deformations in graphene are predicted to give rise to large pseudomagnetic fields. We examine theoretically the case of gas-inflated bubbles to determine whether signatures of such fields are present in the local density of states. Sharp-edged bubbles are found to induce Friedel-type oscillations which can envelope pseudo-Landau level features in certain regions of the bubble. However, bubbles which minimise interference effects are also unsuitable for pseudo-Landau level formation due to more spatially varying field profiles.

Highlights

Strain engineering has been proposed as a method to manipulate the electronic, optical and magnetic properties of graphene [1,2,3,4,5,6,7,8,9,10].It is based on the close relation between the structural and electronic properties of graphene
Sharp peaks, √such as those highlighted by the blue circle and triangle, showing an energy dependence, En ∼ n, are consistent with pseudo-Landau levels (pLLs) arising due to the pseudomagnetic fields (PMFs)
We studied theoretically the local and averaged densities of states in gas-inflated graphene bubbles embedded in infinite graphene sheets using the patched Green’s function approach

Summary

Introduction

Strain engineering has been proposed as a method to manipulate the electronic, optical and magnetic properties of graphene [1,2,3,4,5,6,7,8,9,10].It is based on the close relation between the structural and electronic properties of graphene. The strain field can be coupled to an effective Dirac model of graphene to study the generation of PMFs in various geometries. Patched Green’s function approach The patched Green’s function approach, developed in Ref [14], treats device ‘patches’ embedded within an extended two dimensional system described by a tight-binding Hamiltonian. This approach allows us to insert a single bubble into an otherwise pristine infinite graphene sheet, and avoids issues such as interferences between a bubble and its periodic images or system. The device region Hamiltonian can be tridiagonalized allowing the device region GF to be treated using an adaptive recursive method allowing for efficient calculation of local properties, such as LDOS, everywhere in the device region surrounding a bubble

Strain model

Results

Conclusions