Western Kentucky University
Department of Physics and Astronomy

Colloquium

Dr. Ankur Das

Department of Physics and Astronomy
University of Kentucky

"Graphene in a uniform magnetic field"

April 27, 2020 @ 4:00 pm in ZOOM (Meeting ID: 986 2934 8342)

About the Speaker

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Abstract

The behavior of electrons moving in a two-dimensional (2D) system in the presence of a perpendicular magnetic field is a fascinating topic. The classical Hall effect was discovered in 1879 by Edwin Hall. The quantum Hall effect was discovered about a hundred years later (von Klitzing Nobel 1985). Another discovery that has completely revolutionized modern condensed matter physics is monolayer graphene (Nobel prize 2010). The band structure of monolayer graphene is very interesting and known to have Dirac points inside the Brillouin zone. The quantum Hall effect in graphene was also discovered soon after the discovery of graphene itself. However, people have also discovered the effect of the lattice limit for different lattices. To understand the effect of the lattice one needs to solve the Azbel-Hofstadter problem (proposed by Azbel and solved by Hofstadter). It has been found that for the nearest-neighbor hopping model of graphene has 2q Dirac points in the magnetic Brillouin zone. In our recent paper, we proved that in the presence of the honeycomb lattice symmetries and the chiral symmetry these 2q Dirac points are protected.