Constructing designer materials with engineered electronic properties is one of the emerging topics in condensed matter physics. I will discuss this approach using examples based on atomic manipulation by the tip of a scanning tunneling microscope (STM), molecular self-assembly, and direct growth of hybrid 2D materials to reach the desired structures. Using atomic manipulation, it is possible to construct lattices where every atom is in a well-defined, predetermined position. This opens possibilities for creating artificial materials and I will illustrate this concept by showing how chlorine vacancies on Cu(100) [1] can be used to implement various one-dimensional artificial lattices with topological domain wall states and engineered band structures with flat bands.[2] Similar concepts on designing electronic properties of materials can be realized using metal-organic frameworks (MOFs) as a tuneable platform for achieving materials with engineered electronic structures. I will discuss possibilities of synthesizing 2D-MOFs on weakly interacting substrates and assessing their structure and electronic properties through atomic force microscopy (AFM), STM and scanning tunneling spectroscopy (STS) [3]. Finally, I will outline the kind of engineered electronic states that can be realized using Yu-Shiba-Rusinov (YSR) states in hybrid structures combining magnetic and superconducting materials [4].
References
[1] F.E. Kalff et al. Nat. Nanotech. 11, 926 (2016).
[2] R. Drost et al. Nat. Phys. 13, 668 (2017); Md N. Huda et al., arXiv:1806.08614.
[3] A. Kumar et al. Nano Lett. 18, 5596 (2018); L. Yan et al. ChemPhysChem 20, 2297 (2019).
[4] S. Kezilebieke et al. Nano Lett. 18, 2311-2315 (2018); Nano Lett. 19, 4614-4619 (2019); arXiv:1909.10208.
Prof. Peter Liljeroth heads the Atomic Scale Physics group at Aalto University, Finland. His group focusses on probing the atomic scale structure and electronic properties of molecules, atomically well-defined nanostructures and designer heterostructures of two-dimensional materials using low-temperature scanning tunnelling microscopy (STM) and atomic force microscopy (AFM). Before his appointment at Aalto University, Liljeroth received his Ph.D. thesis from Helsinki University of Technology in 2002 on physical chemistry and electrochemistry. Subsequently, he carried out post-doctoral work at Utrecht University (2003-2006) and IBM Zurich Research Laboratory (2006-2007). He then received a VIDI grant (personal research grant to set up a new research group) at Utrecht University before his appointment at the Department of Applied Physics at Aalto University in 2011. Prof. Liljeroth was part of the team that initiated the atomic resolution imaging of molecules using molecule-modified AFM tips and his group has played a strong role in understanding the contrast formation in these atomically resolved images. Very recently, his team realized topological states in engineered atomic lattices and probed the intrinsic electronic properties of a metal-organic framework synthesized on weakly interacting substrates. Prof. Liljeroth has 87 publications (in total >5400 citations for an h-index of 39). Prof. Liljeroth was awarded the ERC Starting Grant (”Atomically precise nanoelectronic materials”) in 2011, the ERC Advanced Grant (“Artificial Designer Materials”) in 2018 and selected as an Academy Professor of the Academy of Finland in 2018.