Mof

Another installment in the annals of the bullying of the Shockley surface state, this time the trick isn’t exotic adatoms or massive molecular weight, just a 120° tilt of hexaazatriphenylene (HAT) ligands that converts an achiral lattice into a pair of enantiomeric 2-D metal–organic frameworks. The result: chirality-imposed scattering potentials that lift degeneracies and open ΔE ≈ 80 meV gaps in the Ag(111) two-dimensional electron gas while leaving the global periodicity intact. ...

Ben & Bernard’s work on the two-dimensional kagome metal-organic framework is out this week (26 April 2024) in Nature Comms. It was fantastic to see interesting electronic properties emerge at relatively big energy scales for this sort of work, when we were finally able to get the 2d kagome MOF composed of Cu adatoms & DCA molecules, to self-assemble on insulating hexagonal boron nitride (hBN) supported by a Cu111 metallic substrate. We teamed up with Ben Powell’s group at UQ for the many-body expertise required to understand the tunnel junction and substrate work function dependent modulations of the electronic gap in the language of Mott physics. ...

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. ...

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. ...