De-Dimerization Effect and Persistent Current in Mesoscopic Organic Polymer Rings

Abstract

In the framework of the Su-Shrieffer-Heeger (SSH) model, we investigate the effect of Aharonov-Bohm (AB) flux on the dimerization of mesoscopic organic polymer rings. It is shown that an applied AB flux in some flux windows is able to overcome the Peierls instability in mesoscopic organic polymer rings in the reasonably weak electron-phonon coupling regime. The coupling-strength and ring-size dependence of the window size in both half-filled and doped rings are exploited. The nature of the excitations away from half-filling is discussed in the weak coupling regime where there is a de-dimerization window as well as in the strong coupling regime where dimerization prevail at all values of the flux. The plausibility to observe the de-dimerization effect and the persistent current in polymer rings is also addressed.