Spontaneous symmetry breaking by double lithium adsorption in polyacenes

TL;DR

This paper demonstrates that double lithium adsorption on polyacenes induces spontaneous symmetry breaking, leading to significant chain deformation likely caused by Jahn-Teller or Peierls instabilities.

Contribution

It reveals how double lithium adsorption causes symmetry breaking in polyacenes, highlighting a potential link to Jahn-Teller or Peierls instabilities.

Findings

Single lithium causes slight deformation

Double lithium causes dramatic deformation

Symmetry breaking linked to electronic instabilities

Abstract

We show that adsorption of one lithium atom to a polyacenes, i.e. chains of linearly fused benzene rings, will cause this chain to be slightly deformed. If we adsorb a second identical atom on the opposite side of the same ring, this deformation is dramatically enhanced despite of the fact, that a symmetric configuration seems possible. We argue, that this may be due to an instability of the Jahn-Teller type possibly indeed to a Peierls instability.