Tuning the electronic structure of 2d materials via defect engineering and twisting
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Tuning the electronic structure of 2d materials via defect engineering and twisting
Wed, 12/12/2018 - 14:30
Location:
Speaker:
Johannes Lischner
Affiliation:
Imperial College London
Synopsis:
I will discuss two approaches for modifying the electronic structure of 2d materials. First, I will show how charged defects give rise to shallow bound states in semiconducting transition-metal dichalcogenides. Interestingly, the character of the lowest-lying impurity states depends sensitively on the defect charge – both its sign and magnitude. Then, I will discuss twisted bilayer graphene which has attracted considerable attention in recent months because of the experimental observation of significant electron correlation effects and even unconventional superconductivity. These findings are explained using advanced electronic structure methods based on the renormalization group.
Biography:
I am a Lecturer in the Department of Materials and a Royal Society University Research Fellow in the Department of Materials and the Department of Physics at Imperial College London. I am also the Assistant Director of the Centre for Doctoral Training in Theory and Simulation of Materials at Imperial College.
I obtained a Ph.D. in physics from Cornell University in 2010 working in the group of Prof. Tomas Arias. From 2010 to 2014, I was a postdoctoral researcher at UC Berkeley and Lawrence Berkeley National Lab in the groups of Prof. Steven Louie and Prof. Marvin Cohen.
In my research, I study the physical and chemical properties of materials using theoretical modelling approaches. Currently, much of my work is focussed on materials for a sustainable energy technology. For example, I investigate the potential of metallic nanoparticles and organic polymers for solar cells applications and search for photocatalysts that can store the sun's energy in the form of chemical fuels. Another research area I work on are nanomaterials, such as carbon nanotubes or graphene. To learn about the properties of these materials, I employ a variety of modelling techniques ranging from quantum-mechanical approaches, such as many-body perturbation theory (GW/BSE method) or density-functional theory, to classical force fields and elastic continuum models.