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Johannes Margraf

@jtmargraf.bsky.social

All day I dream about science! Computational chemistry, machine learning, electronic structure. https://margraf.uni-bayreuth.de

31 Posts174 Follower247 Folgt
Johannes Margraf@jtmargraf.bsky.social · 5mo ago

I did my first bigger coding project with an llm today (copilot w gpt-5). Usually, for the things I do for research, writing the code is not the time limiting factor, and I do it in python, which I know well. This was for a teaching project involving javascript and html, which I barely know. 1/n

Volker Blum@aimsduke.bsky.social · 5mo ago

Here is Rayan Chakraborty's masterpiece doi.org/10.1021/jacs... showing some new 3D halide perovskites. That's very rare! Again, thanks to Department of Energy, NSF and Duke Climate Initiative. Oh, and a modest 3672 atom DFT simulation probing the local order (along with many other simulations)!

Local Symmetry Breaking in 3D Hybrid Perovskites with 3-Hydroxyazetidinium

Two-dimensional (2D) hybrid perovskite semiconductors with nonprimary ammonium cations (NPACs) have recently attracted interest for spin-optoelectronics owing to the symmetry-breaking distortions in their crystal structures. However, implementing this design strategy in three-dimensional (3D) analogs remains largely unexplored, primarily due to stricter restrictions on cation size. Here, we introduce a family of 3D hybrid perovskites (3DHPs), ASnX3, where A = 3-hydroxyazetidinium (AzOH; +NH2(CH2)2CHOH) and X = Cl, Br, and I. The choice of a bulky NPAC, coupled with the incorporation of a polar group (−OH), targets broken symmetry within the 3D frameworks. While single-crystal X-ray diffraction analysis reveals spatially averaged centrosymmetric cubic (i.e., Pm-3m space group) unit cells, with the largest lattice parameters among existing ASnX3 analogs, first-principles molecular dynamics and electronic structure calculations indicate that the relatively fixed dipoles of AzOH within the SnX6-derived framework introduce local inversion asymmetry and spin polarization. By incorporating a polar cation with limited mobility into the 3D perovskite framework, (AzOH)SnX3 unlocks potential for spin-optoelectronics, photovoltaics, ferroelectrics, and nonlinear optics.

doi.org

Johannes Margraf@jtmargraf.bsky.social · 5mo ago

📢 We're hiring a PhD student in ML for Materials Chemistry at Uni Bayreuth! Apply if you're into atomistic simulations and the intersections between physics, chemistry and ML. We offer a great environment in one of the nicest towns in Germany. Apply here: bit.ly/4aPBgE9. #compchem #chemsky

Job advertisement of the University of Bayreuth  - Chair of Physical Chemistry V: Theory and Machine Learning

Fixed-Term Research Associate (m/f/d, E13 TV-L, 67%) in the field of Machine Learning for Materials Chemistry

uni-bayreuth.de

Lars Fischer@fischblog.bsky.social · 6mo ago

Hi #chemsky, I have been asked to come up with chemistry ideas for a new teaching format at german schools that focuses on democracy. What's lacking are ideas how to use chemistry in this context. So what could be the chemistry of democracy and how do you present it in a school lesson?