Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 87: 2D Materials IV: Charge Density Waves and Electronic Properties
O 87.8: Vortrag
Donnerstag, 4. April 2019, 16:45–17:00, H25
Material Realistic Description of Coulomb Engineering in Two-dimensional Materials — •Christina Steinke1,2, Malte Rösner3, and Tim Wehling1,2 — 1Institute for Theoretical Physics, University of Bremen, Bremen, Germany — 2Bremen Center for Computational Materials Science, University of Bremen, Bremen, Germany — 3Center for Computational Quantum Physics, Flatiron Institute, New York, USA
Heterojunctions are building blocks of various applications in modern optoelectronics. Common heterojunctions rely on interfaces of different materials in order to gain the desired spatial band-gap modulations. We investigate a new type of lateral heterojunction imprinted externally into an otherwise homogeneous monolayer of a 2d material. [1,2] In 2d semiconductors the Coulomb interaction can modify band gaps on an eV scale and can be drastically manipulated by external screening. This allows to tune the local band gaps within a monolayer by laterally structured dielectric surroundings and leads to characteristics of a heterojunction in the local density of states with a spatially sharp band gap modulation. By means of material realistic models based on ab-initio calculations we study the nature and tunability of this band-gap modulation in 2d semiconductors in dependence of the chosen environment and identify optimal candidates for Coulomb engineered 2d systems.
[1] M. Rösner et al., Nano Lett. 16(4) (2016), 2322-2327
[2] A. Raja et al., Nature Communications 8 (2017), 15251