STM studies on K(x)C(60) monolayers reveal new behavior over a wide range of the phase diagram. As x increases from 3 to 5 K(x)C(60) monolayers undergo metal-insulator-metal reentrant phase transitions and exhibit a variety of novel orientational orderings, including a complex 7-molecule, pinwheel-like structure. The proposed driving mechanism for the orientational ordering is the lowering of electron kinetic energy by maximizing the overlap of neighboring molecular orbitals. In insulating (metallic) K(x)C(60) this gives rise to orbital versions of the superexchange (double-exchange) interaction.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevLett.99.086402 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Tuning fulleride electronic structure and molecular ordering via variable layer index.
Nat Mater
March 2008
Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720-7300, USA.
C60 fullerides are uniquely flexible molecular materials that exhibit a rich variety of behaviour, including superconductivity and magnetism in bulk compounds, novel electronic and orientational phases in thin films and quantum transport in a single-C60 transistor. The complexity of fulleride properties stems from the existence of many competing interactions, such as electron-electron correlations, electron-vibration coupling and intermolecular hopping. The exact role of each interaction is controversial owing to the difficulty of experimentally isolating the effects of a single interaction in the intricate fulleride materials.
View Article and Find Full Text PDFNovel orientational ordering and reentrant metallicity in K(x)C(60) monolayers for 3 < or = x < or = 5.
Phys Rev Lett
August 2007
Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, CA 94720-7300, USA.
STM studies on K(x)C(60) monolayers reveal new behavior over a wide range of the phase diagram. As x increases from 3 to 5 K(x)C(60) monolayers undergo metal-insulator-metal reentrant phase transitions and exhibit a variety of novel orientational orderings, including a complex 7-molecule, pinwheel-like structure. The proposed driving mechanism for the orientational ordering is the lowering of electron kinetic energy by maximizing the overlap of neighboring molecular orbitals.
View Article and Find Full Text PDFVisualization of the molecular Jahn-Teller effect in an insulating K4C60 monolayer.
Science
October 2005
Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300, USA.
We present a low-temperature scanning tunneling microscopy (STM) study of K(x)C60 monolayers on Au(111) for 3 < or = x < or = 4. The STM spectrum evolves from one that is characteristic of a metal at x = 3 to one that is characteristic of an insulator at x = 4. This electronic transition is accompanied by a dramatic structural rearrangement of the C60 molecules.
View Article and Find Full Text PDFMonolayer and multilayer structures of C(60), a high temperature van der Waals solid, have been studied with scanning tunneling microscopy. Structures grown on GaAs(110) at 300 kelvin and at elevated temperatures show significantly different morphologies because of balances between thermodynamics and kinetics. Condensation onto stepped surfaces demonstrates preferred bonding and nucleation at step edges.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!