Pinned Low Energy Electronic Excitation in Metal Exchanged Vanadium Oxide Nanoscrolls

摘要

We measured the optical properties of mixed valent vanadium oxide nanoscrollsand their metal exchanged derivatives in order to investigate the chargedynamics in these compounds. In contrast to the prediction of a metallic statefor the metal exchanged derivatives within a rigid band model, we find that theinjected charges in Mn$^{2+}$ exchanged vanadium oxide nanoscrolls are pinned.A low-energy electronic excitation associated with the pinned carriers appearsin the far infrared and persists at low temperature, suggesting that thenanoscrolls are weak metals in their bulk form, dominated by inhomogeneouscharge disproportionation and Madelung energy effects.