October 1, 2019 at 4:30 pm

NQPI Forum | Periodic Strain Induced Moire Patterns in Graphene, Oct. 31

The NQPI Seminar Series presents Md Tareq Mahmud on “Periodic Strain Induced Moire Patterns in Graphene” on Thursday, Oct 31, at 4:10 p.m. in Walter Hall 245.

Tareq is a graduate student in Physics & Astronomy at Ohio University.

Photo of Md Tareq Mamud

Graduate Student Md Tareq Mahmud

Abstract: Local Gaussian-shaped deformations induce strain fields that are represented by scalar and vector potentials in a continuum model description of electron dynamics in graphene. Strain changes the charge distribution in a very peculiar way, introducing a sublattice symmetry breaking, as has been reported in the literature. This feature can be exploited to design specific charge profiles by combining several deformations. Naturally, a combination of two or more is expected to introduce interference effects that can enhance charge accumulation in specific regions. We have investigated the effects of two overlapping deformations with different separations on the local density of states (LDOS). We showed that the overlap term can enhance the LDOS leading to stronger charge confinement in certain regions. Motivated by the work of Mason et. al (2018) we have extended these studies to a closed pack structure with a unit cell of 3 distinct deformations. This arrangement can be extended by symmetry to a lattice superstructure, thus creating a periodic array of confined charge regions, i.e, quantum dots. This array can be tailored by appropriately choosing the parameters of the deformations and their distances. The total charge distribution in these systems is similar to those observed in twisted bilayer systems, known as ‘Moire patterns’. We discuss optimal tuning of deformations to control the physical properties of these graphene devices.

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