Regensburg 2019 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
O: Fachverband Oberflächenphysik
O 5: Nanostructures at Surfaces I: Organics
O 5.2: Talk
Monday, April 1, 2019, 10:45–11:00, H15
Real and k-space fingerprints of a temperature driven phase transition of TPT / Cu(111) — •Lu Lyu1, Benito Arnoldi1, Sina Mousavion1, Sebastian Becker1,2, Maniraj Mahalingam1, Benjamin Stadtmüller1,3, and Martin Aeschlimann1 — 1Department of Physics, TU Kaiserslautern — 2Department of Chemistry, TU Kaiserslautern — 3Graduate School Materials Science in Mainz, Kaiserslautern
The design of 2D porous networks of organic molecules on metal surfaces has become a promising route to design multi-functional porous materials. Using VT-STM, LEED and Laser-ARPES, we investigate the geometric and electronic properties of monolayer 2,4,6-triphenyl-1,3,5-triazine (TPT) on Cu(111) for various sample temperatures. We find a continuously second-order phase transition in the temperature range of 297 K and 106 K, in which the TPT molecules transform from a close-packed structure to a well-ordered nanoporous-network. The mechanism can be understood by the thermodynamic competition between the intermolecular interactions (hydrogen-bonds of TPT peripheral phenyl groups) and the molecule-substrate interaction (central triazine N atoms with surface metal atoms). In the nanoporous-network phase, the standing wave of the electronic charge density can be observed in the cavities of the network in STM which coincides with the appearance of new parabolic surface states close to the Fermi level. Our findings provide a new insight into temperature-dependent electronic structures for 2D organic nanoporous-networks on noble metal surfaces.