The AIP summer meeting was a hybrid event this year 6-9 Dec. ’21 with the border restrictions still in place preventing us from travelling to Brisbane.
Iolanda kindly invited me to talk about Marina’s MgPc hybridization work as well as new results of orbital tomography performed at the Australian Synchrotron (in preparation).
Ben Lowe contributed a talk to the scanning probe microscopy focus session, with an update on how we’re closing in on understanding the mechanism of formation for some unusual metal-organic products identified with ncAFM measurements.
Thanks also to Peggy Schönherr, Peggy Zhang, Peter Jacobson, and Iolanda DiBernardo for contributing talks to the SPM focus session.
Bernard Field talked about how he’s pushing forward how we can rationalise our observations of self-assembled MOF structures, stemming from our recently published experimental results that Agustin talked about in the MOF focus session.
Tag: SPM
Kagome metal-organic framework
Dhaneesh Kumar has extensively studied the on-surface properties of the DCA molecule for his PhD. After getting a good handle on just the DCA on Ag111, we started sprinkling some Cu atoms into the mix.
We observed the same honeycomb kagome structure that forms on Cu111– as seen in an ncAFM force volume shown in the right image. It has also been synthesized on graphene.
The key difference we observed on Ag111 was the Kondo effect, an STS peak at Fermi we tracked up to 150 K!
The consistent spatial distribution of this feature across the MOF was another key observation.
Bernard put in the hard yards with DFT/ +U calculations in conjunction with mean-field Hubbard modelling to rationalise our experimental observations as strong Coulomb interactions between electrons within the kagome MOF.
We’re excited by the possibilities for solid-state architectures to offer further access & control of these intriguing quantum states.
Kumar, D., et. al. (2021). Manifestation of Strongly Correlated Electrons in a 2D Kagome Metal–Organic Framework. Advanced Functional Materials, 2106474. https://doi.org/10.1002/adfm.202106474
Concerted Proton Transfer
We stumbled on a very curious observation in the summer of 2018 with DABQDI molecules provided by Olivier Siri‘s team.
While evaluating its experimental suitability for 1d coordination with metals, which has already proven to be fruitful, we noticed the molecules forming chain-like structures even before we introduced metal adatoms.
The low temperature SPM results are sublime: unusual mechanical stability, distinctive intermolecular bonding, and near-Fermi electronic states lighting up at the ends of the chains.
It took an extraordinary cast of theorists hailing from Pavel’s core group, FZU, Charles, Reykjavik, & Madrid Universities to unravel this puzzle and explain these observations as concerted proton tunneling causing a delocalization of electrons.
“Significance of Nuclear Quantum Effects in Hydrogen Bonded Molecular Chains”, ACS Nano, 2021. 10.1021/acsnano.1c02572