Mg5C60: A stable two dimensional conducting polymer

TL;DR

This paper investigates Mg5C60, a stable 2D fulleride polymer, revealing its high-temperature stability, metallic behavior at room temperature, and a transition to an insulating state below 200 K due to disorder.

Contribution

It provides the first detailed characterization of Mg5C60's structural, spectroscopic, and electronic properties, highlighting its stability and phase transition behavior.

Findings

Mg5C60 is stable up to 823 K.

It exhibits metallic conductivity at room temperature.

Transitions to a paramagnetic insulator below 200 K.

Abstract

We present a study on the structural, spectroscopic, conducting and magnetic properties of Mg5C60, a two dimensional (2D) fulleride polymer. The polymer phase is stable up to the exceptionally high temperature of 823 K. Infrared and Raman studies suggest the formation of single bonds between fulleride ions and possibly Mg - C60 covalent bonds. Mg5C60 is a metal at ambient temperature as shown by electron spin resonance and microwave conductivity measurements. The smooth transition from a metallic to a paramagnetic insulator state below 200 K is attributed to Anderson localization driven by structural disorder.