EU-Aust Colloquium - Strongly correlated pi-magnets driven by e-ph and e-e interaction

Assoc. Prof. Pavel Jelinek, Institute of Physics of the Czech Acadamy of Sciences Recent progress in on-surface chemistry enabled the synthesizing and characterizing of novel-conjugated carbon molecules with magnetic properties systems with unprecedented properties. This route, complemented with high-resolution scanning probe imaging (SPM), provides new opportunities to understand their chemical and physical properties, including the emergence of magnetism in such materials. In the first part of the talk, we will discuss the connection between the topological band structure of -conjugated polymer introduced in the framework of the Su-Schrieffer-Heeger (SSH) model and their conjugation. We will discuss the quantum phase transition between two topologically distinct phases in a π-conjugated polymer. This quantum phase transition is defined by the length of the polymer, triggered by the transition from topologically trivial to a non-trivial phase above a certain polymer length. We demonstrate that pseudo Jahn-Teller effect is the driving mechanism responsible for the quantum phase transition