Berlin 2018 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 47: Theory of electronic structure
HL 47.2: Talk
Thursday, March 15, 2018, 16:30–16:45, EW 202
Dielectric response function in colloidal quantum dots: combining microscopic and macroscopic screening — •Anastasia Karpulevich1,2, Hanh Bui1,2, Zhi Wang1,2, and Gabriel Bester1,2 — 1Institute of Physical Chemistry, Hamburg University, Grindelallee 117, D-20146 — 2The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, D-22761
Dielectric environment profoundly affects the optical properties of colloidal quantum dots (QDs), and modelling of the screening effects remains a challenging task. The recently developed Atomic Effective Pseudopotential (AEP) method provides single-particle energies and wave functions with close to ab-initio quality for colloidal QDs with atomistic passivation [1]. Configuration Interaction (CI) approach was implemented on top of ground-state wave functions to investigate excitonic properties of QDs [2]. We have developed the norm-dependent screening using masking function [3] applied to the individual wave functions. The method offers the opportunity to treat electron-electron interactions fully in reciprocal space, which considerably speeds up calculations, and considers both macroscopic (long-range) and microscopic (short-range) screening effects. The high-level transferability on different semiconductor materials and the influence of the non-polar solvents on the exciton binding energy were demonstrated. The obtained results were compared to the low-temperature experiments as well as to other CI-based models. [1] Karpulevich A. et al. (2016) Phys.Rev.B, 94 [2] Franceschetti A. and Zunger, A. (2000) Phys.Rev.B, 62 [3] Cartoixa X. and Wang L.W. (2005) Phys.Rev.Lett., 94