Institut für Festkörperphysik

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Oliver Hofmann

Institut für Festkörperphysik
TU Graz
Petersgasse 16/3.Stock
8010 Graz
Tel. +43 316 873 8964
Fax. +43 316 873 8466
Mobile: 0650 6345890

   Tuning the Interaction Strength of Inorganic/Organic Interfaces
   Computational Material Design with DFT and Machine Learning
   FWF: Computergestützte Nanowissenschaften
   Charge Injection Layers at Inorganic/Organic Interfaces
   Defects in Organic Monolayers

   Dr. Grygoriy Dolgonos
   Herr Fabio Calcinelli
   Dipl.-Ing., BSc Johannes Cartus
    Andreas Jeindl
   Bsc Lukas Hörmann
   BSc Alexander Egger
   BSc Fabian Weißenbacher

   Computational Planning of Experiments for World-Record Charge-Carrier Mobility Interfaces
   The Missing Link

   Physical Interpretation of Machine Learning Results
   Autonomous Driving for Nanocars

   Computational project: Surface Polymorph Formation
   Structure Search At Interfaces / Machine Learning

   Third Party Funding: 3-year FWF Project
   Huge Computing Time Project Granted
   SAMPLE relearse
   Computing Time Award
   Defects in Organic Monolayers
   IMPRESS workshop at the TUG

Simulation-Driven Material Design

The mission of the Hofman group is the computational discovery of novel materials and material combinations from first principles. We focus on thin film and interfaces, that are of technilogical relevance for nanotechnology applications, such as organic solar cells and OLED displays. We focus on organic thin films, which often assume particular polymorphs and exhibit properties superior to that of the bulk.

To achieve this mission, my group and I pursue two complementary avenues. One part applies density functional theory (DFT) to pertinent surface science problems at inorganic/organic interfaces, with the goal to identify and push back the limits of the state-of-the-art methodology. The second part of my group develops the machine-learning algorithm "SAMPLE" to predict the structure and the properties of thin film polymorphs.

We are presently working on three complimentary FWF-funded projects. In "Tuning of the Interaction Strength", the purpose is to choose the substrate on which the thin film are grown, in order to obtain materials with specific, desired properties. The project "Defects in Organic Monolayers" investigates the nature and the impact of defects and disorder on the electronic structure. Finally, the project "MAP-DESIGN" aims to develop recipies, which allow to produce predicted materials also experimentally. This will close the gap between computational material design and its realization in a lab.

Our research interests include
  • Structure Determination and Prediction
  • Polymorphism and Metastable Phases
  • Phase Diagrams and Phase Transformations
  • Charge and Energy Transfer Across Interfaces
  • Adsorption Processes of Organic Molecules
  • Defects in Organic Monolayers
  • Spontaneous Symmetry Breaking in Adsorbate Layers
  • Doping and Long-Range Band-Bending in Semiconductors
which we study (mostly) with the these techniques:
  • Density Functional Theory (semilocal and hybrid functionals)
  • Band Structure Calculations
  • Machine Learning (mostly Gaussian Process Regression)
  • Ab-initio Thermodynamics
  • Charge-Reservoir Electrostatic Sheet Technique (a QM/MM approach)
(Some) Master and Bachelor projects can be found using the links on the left side of this page. Usually, more are available - inquire within.

Personal data

Featured Videos of Recent Talks and Papers

"Surface Adsorbate Polymorph Prediction with Little Effort - Talk at IPAM, LA, Oct 2017

Video of the talk Surface Adsorbate Polymorph Prediction with Little Effort given at the Optimization and Optimal Control for Complex Energy and Property Landscapes workshop at Los Angles, USA, in Sept 2017.

Video of the talk "Nuts and Bolts of Density Functional Theory", given at the FHI-aims Hands-on Workshop in Berlin, July 2017.

Video abstract for "Doping dependence of the surface phase stability of polar O-terminated (000-1) ZnO", published in The New Journal of Physics, 19 (8), 083012, 2017

Highlighted publications (open access)

O.T. Hofmann, P. Rinke, M. Scheffler, G. Heimel, "Integer versus Fractional Charge Transfer at Metal(/Insulator)/Organic Interfaces: Cu(/NaCl)/TCNE", ACS Nano just accepted, doi: 10.1021/acsnano.5b01164

O.T. Hofmann, V. Atalla, N. Moll, P. Rinke, M. Scheffler, "Interface dipoles of organic molecules on Ag(111) in hybrid density-functional theory", New Journal of Physics, 15, 123028 (2013), doi: 10.1088/1367-2630/15/12/123028

O.T. Hofmann, J.C. Deinert, Y. Xu, P. Rinke, J. Stähler, M. Wolf, M. Scheffler, "Large work function reduction by adsorption of a molecule with a negative electron affinity: Pyridine on ZnO(1010)", Journal of Chemical Physics 139, 174701 (2013) doi: 10.1063/1.4827017

Y. Xu, O.T. Hofmann, R. Schlesinger, S. Winkler, J. Frisch, J. Niederhausen, A. Vollmer, S. Blumstengel, F. Henneberger, N. Koch, P. Rinke, M. Scheffler, "Space-Charge Transfer in Hybrid Inorganic-Organic Systems", Physical Review Letters 111, 226802 (2013) doi: 10.1103/PhysRevLett.111.226802

A. Tkatchenko, L. Romaner, O.T. Hofmann, E. Zojer, C. Ambrosch-Draxl, M. Scheffler: "van der Waals Interactions Between Organic Adsorbates and at Organic/Inorganic Interfaces", MRS Bulletin 35, 435 (2010). doi: 10.1557/mrs2010.581

O.T. Hofmann, D.A. Egger, E. Zojer, “Work-function modification beyond pinning: When do molecular dipoles count?”, Nano Lett. 10, 4369 (2010). doi: 10.1021/nl101874k

Contributor to the FHI aims package

last updated: 04. Jan 2019