Nanoscale Science Department

We develop a methodology that allows glycans (carbohydrates) bonded to proteins and lipids to be directly observed. Glycan-decorated molecules are deposited on surface by electrospray deposition for their imaging at cryogenic temperatures. Direct imaging of these glycan-decorated molecules using a Scanning Tunnelling Microscope permits all glycan structures in a protein or a lipid to be determined at the single molecule level. Our approach opens new opportunities to determine structures of many more glycan-decorated molecules that play central roles in our health and diseases.

Can one see how atoms move inside a single molecule? By performing ultrafast spectroscopy in a scanning tunneling microscope, researchers from Max Planck Institute for Solid State Research (MPI-FKF Stuttgart) and Autonomous University of Madrid (UAM) showed that the periodic motion of the atoms (vibrations) in a single molecule can be captured and precisely controlled. The work opens the path to directly capture the snapshots of atomic motion in molecules/materials undergoing chemical/phase transformations.

We discover that landing macromolecules on an one-atom-thick membrane, like graphene, preserves the gas-phase 3D-structure of the molecules at the surface. By exploiting this dynamics for proteins landing on graphene, we are able to land folded proteins on surface and see them one-at-a-time by low-energy electron holography technique. Our approach opens new opportunities to visualize 3D-structures of many proteins, nucleic acids, and carbohydrates at the single molecule level.

Interference requires coherence, which is usually hard to come by in condensed matter environments. However, sometimes even short coherence times are suffcient to reveal most peculiar phenomena such as making it look like a supercurrent reverses its flow, which can be exploited for quantum sensing. An  international collaboration of scientists between the Max Planck Institute for Solid State Research in Stuttgart, Ulm University, the Autonomous University of Madrid, and the University of Uppsala has now used such a supercurrent reversal to detect the ground state of a magnetic impurity coupled to a superconductor. Using a scanning tunneling microscope, they detect the interference in the Josephson current thereby creating a rudimentary phase sensitivity like in a superconducting quantum interference device (SQUID).