Evidence for distinct polymer chain orientations in KC60 and RbC60

TL;DR

This study reveals that KC60 and RbC60 have different polymer chain orientations, identified through single crystal X-ray diffraction, which may explain their contrasting electronic properties.

Contribution

The paper provides the first direct structural evidence of distinct chain orientations in KC60 and RbC60 using advanced diffraction techniques.

Findings

KC60 and RbC60 have different chain orientations.

KC60 belongs to space group Pmnn, RbC60 to I2/m.

Structural differences are crucial for understanding their electronic properties.

Abstract

The KC60 and RbC60 polymer phases exhibit contrasting electronic properties while powder diffraction studies have revealed no definite structural difference. We have performed single crystal X-ray diffraction and diffuse scattering studies of these compounds. It is found that KC60 and RbC60 possess different chain orientations about their axes, which are described by distinct space groups Pmnn and I2/m, respectively. Such a structural difference will be of great importance to a complete understanding of the physical properties.