Visualizing molecular orientational ordering and electronic structure in CsnC60 fulleride films

Abstract

Alkali-doped fullerides exhibit a wealth of unusual phases that remain controversial by nature. Here we report a cryogenic scanning tunneling microscopy study of the sub-molecular structural and electronic properties of expanded fullerene C60 films with various cesium (Cs) doping. By varying the discrete charge states and film thicknesses, we reveal a large tunability of orientational ordering of C60 anions, yet the tunneling conductance spectra are all robustly characteristic of energy gaps, hallmarks of Jahn-Teller instability and electronic correlations. The Fermi level lies halfway within the insulating gap for stoichiometric Cs doping level of n = 1, 2, 3 and 4, apart from which it moves toward band edges with concomitant electronic states within the energy gap. Our findings establish the universality of Jahn-Teller instability, and clarify the relationship among the doping, structural and electronic structures in CsnC60 fullerides.

9 pages, 6 figures

References in corpus (13)

• Charge ordering in the TMTTF family of molecular conductors
• Electron--Vibron Interactions and Berry Phases in Charged Buckminsterfullerene: Part I
• Electron--Vibron Interactions in Charged Buckminsterfullerene: Pair Energies and Spectra (Part II)
• Unified understanding of superconductivity and Mott transition in alkali-doped fullerides from first principles
• Non magnetic molecular Jahn-Teller Mott insulators
• Tuning fulleride electronic structure and molecular ordering via variable layer index
• Charge disproportionation, mixed valence, and Janus effect in multiorbital systems: A tale of two insulators
• Spontaneous orbital-selective Mott transitions and the Jahn-Teller metal of A${}_3$C${}_{60}$
• NMR study of the Superconducting gap variation near the Mott transition in Cs${}_3$C${}_{60}$
• Novel Orientational Ordering and Reentrant Metallicity in KxC60 Monolayers for 3 <= x <= 5
• Orbital disproportionation of electronic density - a universal feature of alkali-doped fullerides
• Spontaneously orbital-selective superconductivity in a three-orbital Hubbard model
• Nanoscale orbital excitations and the infrared spectrum of a molecular Mott insulator: A15-Cs${}_3$C${}_{60}$

Cited by in corpus (5)

• Coexistence of full-gap superconductivity and pseudogap in two-dimensional fullerides
• Tuning the electronic states and superconductivity in alkali fulleride films
• Entropy and electronic orders of the three-orbital Hubbard model with antiferromagnetic Hund coupling
• Spin-orbital model for fullerides
• Merohedral disorder and impurity impacts on superconductivity of fullerenes