Spatially-resolved electronic and vibronic properties of single diamondoid molecules

Abstract

Diamondoids are a unique form of carbon nanostructure best described as hydrogen-terminated diamond molecules. Their diamond-cage structures and tetrahedral sp3 hybrid bonding create new possibilities for tuning electronic band gaps, optical properties, thermal transport, and mechanical strength at the nanoscale. The recently-discovered higher diamondoids (each containing more than three diamond cells) have thus generated much excitement in regards to their potential versatility as nanoscale devices. Despite this excitement, however, very little is known about the properties of isolated diamondoids on metal surfaces, a very relevant system for molecular electronics. Here we report the first molecular scale study of individual tetramantane diamondoids on Au(111) using scanning tunneling microscopy and spectroscopy. We find that both the diamondoid electronic structure and electron-vibrational coupling exhibit unique spatial distributions characterized by pronounced line nodes across the molecular surfaces. Ab-initio pseudopotential density functional calculations reveal that the observed dominant electronic and vibronic properties of diamondoids are determined by surface hydrogen terminations, a feature having important implications for designing diamondoid-based molecular devices.

16 pages, 4 figures. to appear in Nature Materials

References in corpus (3)

• The SIESTA method for ab initio order-N materials simulation
• Efficient index handling of multidimensional periodic boundary conditions
• Electron Emission from Diamondoids: A Diffusion Quantum Monte Carlo Study

Cited by in corpus (7)

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• Functionalized adamantane: fundamental building blocks for nanostructure self-assembly
• Quantum Monte Carlo, time-dependent density functional theory, and density functional theory calculations of diamondoid excitation energies and Stokes shifts
• Structural, Electronic, and Vibrational Properties of Amino-adamantane and Rimantadine Isomers
• Domains of doping in graphene on polycrystalline gold: first-principles and scanning tunneling spectroscopy studies
• Magic Numbers for Packing Adamantane in Helium Droplets: Cluster Cations, Dications and Trications
• Intermolecular interactions and substrate effects for an adamantane monolayer on the Au(111) surface