Polymeric methyltrioxorhenium (poly-MTO) represents the first example of an inherent conducting organometallic oxide. It adopts the structural motives and transport properties of some classical perovskites in two dimensions. In this study we present resistivity data down to 30 mK which exhibit a crossover from a metallic (dρ/dT> 0) to an insulating (dρ/dT< 0) behavior at about 30 K. Below 30 K an unusual resistivity behavior, similar to that of some doped cuprate systems, is observed: initially the resistivity increases approximately as ρ∼ log(1/T) before it starts to saturate below 2 K. Furthermore, a linear positive magnetoresistance is found (up to 7 T). Temperature dependent magnetization and specific heat measurements in various magnetic fields indicate that the unusual resistivity behavior may be driven by spatial localization of the d1 moments at the Re atoms.
@article{arxiv.cond-mat/0504585,
title = {Possible Localization Behavior of the Inherent Conducting Polymer (CH$_3$)$_{0.9}$ReO$_3$},
author = {E. --W. Scheidt and R. Miller and Ch. Helbig and G. Eickerling and F. Mayr and R. Herrmann and P. Schwab and W. Scherer},
journal= {arXiv preprint arXiv:cond-mat/0504585},
year = {2007}
}