A Resonant Photoemission Insight to the Electronic Structure of Gd Nanowires Templated in the Hollow Core of SWCNTs

Single wall carbon nanotubes (SWCNTs) are archetypical 1D systems with peculiar electronic properties which can be modified in a controlled manner by various methods. One of these is filling the hollow core with metallofullerenes. Additionally, subsequent modifications can be induced utilizing the nanotube hollow space as a nano-reactor. Here we show the electronic structure changes of Gd@C82 peapods upon transformation into Gd nanowires encapsulated in SWCNTs. This has been monitored by a combined high resolution photoemission and X-ray absorption study. From a detailed analysis of the Gd 3d, 4d, 4f and C1s responses, as well as the valence band resonant photoemission, we were able to elucidate the changes in the bonding environment and charge transfer in these 1D systems. We observe a clear modification of the low energy electronic properties of the SWCNT transformed partly into dou- ble walled tubular structures with encapsulated Gd nanowires.