Length driven topological phase transition in polymers

We employed scanning probe microscopy to explore atomic scale control over quantum phase transitions between two different topological quantum states of a well-defined π-conjugated polymer. The phase transition is driven by a pseudo Jahn–Teller effect that is activated above a certain polymer chain length. In addition, theoretical calculations indicate the presence of long-lasting coherent fluctuations between the polymer's two quantum phases near the phase transition, at finite temperature.

H. González-Herrero,J. I. Mendieta-Moreno,Sh. Edalatmanesh,J. Santos,N. Martín,D. Écija, B. de la Torre,P. Jelinek

Atomic Scale Control and Visualization of Topological Quantum Phase Transition in π-Conjugated Polymers Driven by Their Length
Adv. Mater. 33 (2021) 2104495(1) - 2104495(9).