Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 90: Electronic structure III
O 90.4: Vortrag
Donnerstag, 17. März 2011, 18:00–18:15, WIL C107
From Molecule to Monolayer: Self-Induced Quantum-Confined Stark effect in Monolayers of Polar Molecules — •Ferdinand Rissner1, David A. Egger1, Amir Natan2, Thomas Körzdörfer3, Stephan Kümmel3, Leeor Kronik2, and Egbert Zojer1 — 1Institute of Solid State Physics, TU Graz, Graz, Austria — 2Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth, Israel — 3Physikalisches Institut, Universität Bayreuth, Bayreuth, Germany
Using density functional theory calculations, the electronic structure of the polar molecule terpyrimidinethiol is investigated in gas phase and in a 2D-periodic self-assembled monolayer (SAM). We find that hybrid functionals give qualitatively different results compared to a (semi-)local description and rationalize this finding in terms of an orbital-dependent self-interaction error.
Upon self-assembly, we observe orbital energy shifts depending on the spatial structure of the orbital, which can render the ordering of the states a function of the SAM packing density. Related to this, the energy gap is modified and the symmetry of the frontier orbitals can change. Occupied and unoccupied frontier orbitals localize on opposite sides of the monolayer as known from the quantum-confined Stark effect. All this is caused by the internal electric field originating from the molecular dipole moments.